john holt reports from you on mexico's border with united states where many migrant say they've suffered too much to return home. now . medical this is how one us border patrol officer receive patient migrant crossing the rio grande. they coming back with food to camp. they've set up in texas. you women are just what the oh. 6 no, no, no, no, no, no, no, no, no, no. i mean we've got our families inside dying of homeless. it had to go out to buy the, we can see this one is still getting back in for the come up. so they went across to mexico to get food. they said, because there isn't enough food for them to be there. in the there's more than 12000 migrants, mostly haitians in the kansas sprung up in del rio, texas. over the last 2 weeks. they want asylum. the us authorities are overwhelmed . this is just the latest splash point in a month from surge of people illegally crossing the border. and there's little in the camp for them. and of course, i found a sanitary product. there aren't any food there isn't any either. they don't give you anything. we met nicholas on the mexican bank of the

estimated. 13000 people are staying at a make shift. camp in the texas bought a ton of dell rear and as john holt reports thousands more waiting to enter the u. s. from mexico, from the mexican side right now of the rio grande, a, that's the river that separates this country from the united states. and we here because more than 10000 people, most of them haitian, crossed the river to get to the united states and establish a sort of mate ship, have one thing to be given asylum and to be able to stay in the united states. many of them travel through south and central america to get to this point. they flee poverty and years of political turmoil and natural disasters. back home, i did. i thought that remote or not, i'm really scared, you know why haiti had enough quick. we were left with nothing, no home, no food, nothing, almost all my family died. and if we don't go across where we go to go, we don't have a home. that's why with searching for a better future. the flow of patients crossing to the united states at this point suddenly turn into a torrent of the last week or 2. but now it's slow. agai

i want to bring in john holt crist, the vice president from one of the firms behind tracking this stuff is damaging enough. spreading lies and so on. but to physically mobilize protesters in the streets, that is particularly alarming. >> yeah, this is something that we haven't seen for a while, since the russians under the internet research agency put people on the streets to -- in cages to address hillary clinton and on opposite sides of rallies around black lives matter. this is really these chinese operators moving in the same direction. >> let me ask you this. because with china and russia and these kind of campaigns, a big advantage for these foreign countries attacking the u.s. that they have an easy target here. because they're not creating these divisions over this stuff. they're trying to take advantage of existing divisions. and by the way, existing domestic sources of disinformation mong-- among thee former president. >> they're about promoting narratives that portray the u.s. as chaotic and disorderly. and unfortunately there have been a lot of very real incidents that they'

john o'neill. 20 year later, how is the u.s. adapting to keep america safe? on nightly news with lester holt, peter williams looks at advancements and one of the newest dangers. >>> one of the services in the bay area tomorrow will be at the flight 93 memorial in union city. it was bound for sfo when it was hijacked and ended up crashing in a pennsylvania field. nbc's ""dateline"" focuses entirely on flight 93, how it happened, the heroes, passengers and their families. bob radell has a look from union city. >> reporter: as you can see behind me, workers are spiffying up the flight 93 memorial here m in union city for a special memorial. it was september 11, 2001 when it was supposed to land at sfo with 33 passengers, seven crew members, plus the terrorist hijackers. sadly, it never made it. it krashed on a field in pennsylvania. on board, mark bingham, traveling from his new york office to his san francisco office, he was among the passengers who fought back against those hijackers. who had intended to divert the plane to washington, d.c. but because of his bravery and that of many others,