fourth of july holiday weekend. >> thanks, rob. lester holt is next with nightly news. themselves up. breaking news tonight, a major terrorist attack at the airport in istanbul. multiple suicide bombers blow themselves up. many u.s. flights to turkey are grounded. the president being briefed. was it isis and what about security at home? richard engel is live at the scene of the attack in istanbul. no smoking gun, republicans release the benghazi report after years of investigations. no bombshells about hillary clinton but tonight there are troubling new questions about the u.s. response that night. train explosion, the search for the missing tonight after a massive collision on the tracks. and remembering pat

summit, tributes for one of the greatest coaches of all time. "nightly news" begins right now. lester holt. >> good evening. a scene of carnage amid a rising death toll at the international airport at istanbul, turkey after multiple suicide bombings left 60 dead. multiple injured. witnesses described as many as three explosi explosions. one of them in this video appears to be the lower level of the international terminal. it appears to be the lower level of the international level. the tape not verified by nbc news. in another unverified video, an attacker appears to be shot by police and moments later detonates his explosives. it was late evening in istanbul when the terror attack happened. the explosion sending passengers and workers scrambling for cover. nbc's bill neely has late details.

>> reporter: it's minutes after the bombs exploded scores are dead and injured and there is panic. hundreds of passengers and their families are fleeing the main airport in istanbul. turkish officials say at least three suicide bombers blew themself up at the arrival area of the main terminal. >> this happened at the arrivals area. >> yes. in arrivals, yes. >> did you hear an explosion? was there gunfire? >> you know, a lot of guns. >> reporter: they would open fire first with automatic weapons. police returned fire but it didn't stop the terrorists. this cctv footage on a computer appears to show the moment of one of the explosions. this was a coordinated, as well as a deadly assault on the third busiest airport in europe. it was crowded as the terrorists struck. they reached a security checkpoint but didn't get inside the main hall. another video appears to show one of the gunmen getting shot,

falling and detonating his explosives. as ambulances arrive to recover the dead and wounded, taxi drivers leaving the terminal shouted, don't enter, a bomb has exploded. it's not the first time istanbul's airports have been attacked. no one has yet claimed this attack but suspicion is falling on two groups, isis and kurdish separatists. turkey and istanbul braced for more and angry. bill neely, nbc news london. >> we want to go to richard engel in istanbul. he's made his way to the airport. richard, what can you tell us from there? >> reporter: well, the police have sealed off this area. we can't get any closer to the terminal which you can see behind me. we see startled passengers coming out here carrying their babies, dragging their luggage. we reported several weeks ago, lester, that isis had forward deployed more than 35 militants from syria

to turkey with the intention of carrying out attacks on an international scale during the month of ramadan. ramadan is supposed to last for one more week. today i was told this attack was highly likely the work of those same militants who had been forward deployed and this could be just the start of a series of attacks before ramadan is over. >> all right. richard engel in istanbul for us. thank you, richard. the attack comes three months after the attacks at brussels, including the airport bombing in which international travelers seem to be among the intended targets. the security is very much of concern to american aviation officials that must ensure foreign airports offer security as good or better as those in the u.s. nbc's tom costello has the breaking story. >> reporter: the biggest concern to u.s. aviation security analy analysts, that an overseas terrorist will get on a u.s.-bound flight

attacking passengers and the plane or landing in the u.s. and staging an attack here. any foreign airport with direct flights to the u.s. must comply with tsa airport security protocols. tsa visits them undercover. >> at the tsa chief. >> we inspect those airports to ensure they meet the standings and that requires -- that includes the people on the aircraft, the crews that manage the aircraft, the people that service the aircraft and cargo on board. >> reporter: it was just three months ago the terrorists attacked the airport and subway station in brussels. 32 dead and 300 injured. hubs remain attractive soft targets because of the potential for mass casualties while inflicting economic harm. in the u.s. perimeter security can vary from airport to airport and the number of armed police are determined by local jurisdictions. >> airports aren't built with castles . they are not built with security in mind, quite frankly. a lot are built for shopping. transportation and shopping. >> reporter: whether overseas or at home,

security experts say they rely on the public's help. watch out for people that seem to be surveilling a location, gathering information about patterns like shift changes and testing security perhaps with false alarms. tonight federal authorities report no immediate change to the security posture of airports here in the u.s. but some cities like the new york city airport, there will be highly visible police tactical units on patrol, lester? >> thank you. we'll continue to monitor the situation in istanbul and bring you the latest developments. we do want to switch gears to another attack at the u.s. consulate in benghazi. one done by house republicans. it does raise questions about the u.s. response that night. nbc's andrea mitchell reports. >> reporter: benghazi in flames and the death of four americans including u.s. ambassador chris stevens. four years and eight congressional

investigations later. including an 11 hour marathon with hillary clinton last fall. in an 800-page report today, house republicans blaming the white house, state department and pentagon especially the military for not deploying for nearly 11 hours after the first shots were fired. >> not a single wheel was turning towards libya. >> reporter: but no smoking gun against hillary clinton for failing to protect her diplom diplomats. >> the degree which republicans are willing to play politics with their deaths and this tragedy is appalling. >> reporter: on the night of the attack, a two-hour white house video conference with the pentagon and clinton, state department officials arguing the marines should wear civilian clothes to avoid upsetting the new libyan government. one commander telling investigators when they finally had a plane during the course of three hours, he and his marines changed in and out of uniforms four times. officials missing warnings not anticipating the second attack that

killed two more americans. the vice chairman of the joint chiefs skipping the meetings to host a dinner party at home. >> we've been told forever now no military asset could reach benghazi in time and we know that's true because nothing was headed toward benghazi. >> reporter: and no evacuation plan. the cia relying on former soldiers from their old enemy moammar gadhafi to rescue the last 35 americans. still, with no evidence of clinton's role. >> i'll leave it to others to characterize this report but i think it's pretty clear it's time to move on. >> reporter: but donald trump isn't letting go tweeting benghazi is another hillary clinton failure. the committee spent two years and $7 million along the way stumbling into the fact that clinton used a private e-mail server that could be the most important result of the committee's work, lester? >> andrea mitchell, thank you. newly obtained surveillance video shows dramatic moments when a man was shot on

the white house grounds last month. the secret service said he was shot for refusing to drop the gun he was carrying and caution, one of these scene is pretty graphic. pete williams has details. >> reporter: word of shots fired at the white house put washington on edge last month. a newly released surveillance video dramatically reveals what happened. the secret service says a 31-year-old man jesse olivien of pennsylvania walked toward the white house on the afternoon of may 20th, carrying a handgun. it's clearly visible in his right hand. secret service takes positions. he continues walking ignoring commands to drop the gun. as he approaches security checkpoints still disobeying the commands, a secret service agent out of frame to the left shoots him once. they handcuff him. others arrive to render first aid. he survives the gunshot and is taken to a waiting ambulance and on to a hospital for surgery. on monday his lawyer asked that he be released to home detention pending trial but the judge said he's a danger to

the community. the secret service says he told an officer he came to the white house quote to shoot people. pete williams, nbc news, washington. a number of crew members are missing after two trains collided in a fiery head-on cash in texas. boxcars erupted in a ball of flames forcing authorities to evacuate nearby residents out of fear for their safety. nbc's gabe gutierrez has the latest. >> reporter: in north texas today, a blazing inferno, this video capturing the moments after impact showing boxcars falling like dominos next to a growing fire ball. just before 9:00 a.m. two freight trains 30 miles northeast of amarillo, colliding near the town of panhandle. cargo containers crumbled and burning as authorities rush to rescue the crew members on board. >> do we have any entrapment at this time? >> yes, sir, we have three. >> reporter: county officials say one of four crew members jumped from one of the trains and is in the

hospital and three others are still missing. >> we're at a standstill trying to get the fire contained. >> reporter: after last year's amtrak derailment in philadelphia, federal officials called for more use of positive train control, gps technology for preventing collisions. in this case, the burlington northern santa fe railway company which owns both trains says it appears this is the type of the incident that ptc is intended to prevent. this is why we have been aggressively deploying ptc across our network. voluntary evacuations are now underway. >> just a massive black smoke coming up, you know, just like burning up diesel fuel. >> reporter: so far no word on what caused the crash. gabe gutierrez, nbc news. tonight, tributes are pouring in from across the country for one of the greatest coaches of all time. pat summitt, a long-time coach of the lady vols who led to eight national championships died after a battle with early onset

alzheimer's disease. she was just 64 years old. nbc's cynthia mcfadden looks back at her extraordinary life. >> reporter: pat summitt had a lot of experience with winning. no woman or man ever won more college basketball games than she did. nearly 40 years at the university of tennessee her beloved lady vols never lost a season. all her charm -- ♪ >> reporter: she was a fierce competitor and none of her players wanted to receive her steely blue stare after a bad play. >> she was constantly on me to every day get better and push myself to her standard. >> reporter: and summitt's standards were high. her team won eight national championships but the best stat, 100% of the young women who played four years for her graduated from college. >> you never took shortcuts.

you did things the right way. i mean, she never had a bad day. she never had an off day, and she meant a lot to me. >> reporter: in the end, she was a life coach as much as a basketball one. >> i shared my health concerns with you. >> reporter: announcing five years ago she had been diagnosed with early onset alzheimer's at only 59. >> my mom says it is what it is but it will be what you make it. >> reporter: in 2012 she was awarded the presidential medal of freedom. >> anybody that feels sorry for pat will find themselves on the receiving end of that famous glare or she might punch you. >> reporter: her toughness securing her legacy not as the woman's basketball coach but as one of the greatest coaches of all time. cynthia mcfadden, nbc news, new york. >> incredible legacy. still ahead tonight, the regular exam that millions of women dread but now there is new word that for many it may not be necessary at all. more about that. also, the urgent rescue mission to save

the life of one of the ocean's most majestic creatures.

we're back now with new concerns being raised about an exam that over 60 million get every year. year. pelvic exams have long been considered key to women's health but uncomfortable and intrusive and as nbc's ann thompson tells us a panel of experts is questioning whether they are reliable or worthwhile. >> reporter: it is a staple of women's health. the often dreaded

pelvic exam performed in 76% of visits to oeb ob/gyn but today a government advisory panel says there is inadequate evidence this annual exam helps detect cancers, infections or sexual transmitted diseases in healthy women. >> we don't know what the benefits associated with the pelvic exam based on the evidence that we currently have. >> reporter: there's also the question of harm, such as false positives that can lead to additional tests and costs and false negatives that can incorrectly reassure women. there is wide agreement that pelvic exams are beneficial for pregnant women or those with symptoms of gynecological problems. ob/gyn doctor timyka august says today's news is a good start for discussion. she tells healthy patients the pelvic exam is optional. >> the majority of women absolutely want it. absolutely. they just want to make sure everything is okay. >> i'm not worried about my discomfort if it's something that can be life-changing or

saving. >> reporter: the american college of obstetricians and gynecologists still recommends the annual exams for women over 21 but concedes they have limitations. today's report comes from the same group that questioned long-use screening tests like mammograms and tests for prostate cancer, now seeking solid scientific evidence for what have become medical rituals. ann thompson, nbc news, new york. we're back in a moment with the ballpark intruder that caused a very close call.

we're back with a delicate rescue mission under way off the coast of southern california this evening. it's to save an endangered blue whale entangled in fishing line. the struggling whale was first spotted three days ago but on the move and time is of the essence to save it. miguel almaguer is with rescue teams. >> reporter: an urgent rescue mission to save an endangered blue whale 30 miles off the coast of southern

california. this 70-foot whale is entangled in 200 feet of fishing line and crab traps dragging up to 300 pounds of debris from its mouth and tail. for three days rescue teams have been trying to cut it free. >> with it being down 25, 30 feet into the water, it was almost impossible to really help it but i don't think he knew we were trying to help him because he took off on us after we got real close to almost getting him. >> reporter: blue whales are largest in the world and by nature elusive. this blue in 2015 disappearing into the ocean after its rescue attempt failed. abandoned in lost fishing gear is the number one cause of death for marine wildlife. to successfully pull off this rescue mission, crews will need a bit of luck. >> we have to be cautious because when you're next to an animal that size the potential for danger and human bodily harm

is definitely there. >> reporter: with no way to track the whale, rescue teams are searching the vast ocean hoping to find and save one of the world's most majestic creatures. miguel almaguer, nbc news, dana point, california. this maybe the closest call we've seen on a baseball diamond all season. take a look. a bird flying right in front of home plate during last night's cardinals royals matchup barely missing an 84 mile an hour pitch and the swing of the bat. luckily escaped with just a few ruffled feathers. look at that. when we come back, cancer moon shot. the doctor fighting to make sure all children get a fighting chance.

===raj/take vo=== the new tactics that could mnth. ===jess/take vo=== plus, nbc bay area respondsafte make. finally tonight, we're on the eve of a major summit for the cancer moon shot initiative led by vice president joe biden. among the goals, increasing access to cutting edge treatment, so when it comes to children, one doctor found that not all treatments are equal. rehema ellis explains what she's doing about it to save lives. >> reporter: it should have been the happiest time of her life but three days after her son was born, 19-year-old rayleen was diagnosed with leukemia. >> he's the main

reason i'm fighting so hard. >> in her corner one of the best cancer doctors in the country. at the university of new mexico comprehensive cancer center, doctors transformed cancer care for hispanics and indian americans dying of cancer at an ala alarming rate. >> i've been a warrior woman. >> reporter: she needed to be. dr. wilman was startled to find in new mexico native american and hispanic children had a nearly zero survival rate compared to white children with leukemia on standard chemotherapy. in an unusual move, dr. willman and some of the country's top leukemia researchers joined force analyzing millions of genetic patterns and find native american and hispanic children had different genetic mutations than white children and needed treatments tailored just for them. >> the revolution in

cancer medicine today really is personalized medicine. >> reporter: rayleen got that in a cutting edge cancer technique called genetic sequencing and then her own individual drug treatment. is there a benefit nationwide? >> there's no question. our ability to develop new treatments greatly impacts the care of children everywhere. >> reporter: today she is in remission recovering at new mexico children's hospital. colorado. and now with the help of her cancer moon shot team she just might. rehema ellis, nbc news albuquerque. tomorrow on "nightly news" our special series goes inside the cancer moon shot program when joe biden sits down with tom brokaw. that will do it for us on this tuesday night. i'm lester holt. for all of us at nbc news, thank you for watching and good night. test test test test test test

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but one flight out of sfo iexpet minutes headed the very airpora. turkey are grounded this hour, but one flight is expected to ack off in just minutes headed to that very airport attacked in istanbul. it is now 4:00 in the morning in turkey, five and a half hours after a deadly attack at the aturak national airport. gunmen set off bombs inside the area. at least 36 people are dead and hasns others injured, but that warder keeps climbing. no word yet on any american casualties. how many gunmen were on the ground is unclear, but nbc has learned that isis had deployed more isis to turkey during the ramadan. ae do have to tell you the images can be disturbing. aatch closely.