Transcript for Humanitarian concerns grow over exodus of Central Americans

More on that migrant caravan. We've been with them on the ground and the group now 7,000 people strong and our cameras are finding so many families struggling, sacrificing it all in hopes of a better life. Our chief national correspondent Matt Gutman is with the caravan in Mexico. Good morning, Matt. Reporter: Hey, good morning. Over the past couple of days we've watched this caravan's ranks swell from 3,000 to the 7,000 that you just mentioned. I'll have my cameraman spin around so you can see this is what it looks like after 50 miles of marching over two days. People using every single square inch of this town square. You can see families over here and right by me and with little food, no services and no bathrooms, people here are starting to get sick. This morning, mounting concerns of a humanitarian crisis building for this exodus of Central Americans. This ribbon stretching over ten miles over southern Mexico's ads. Over marching 50 miles in two days they finally bedded down. This woman bringing her infant to an ambulance with heat exhaustion. Others tending to battered feet and bodies. Five miles into their March Monday they reached the town of viva Mexico. Good samaritans ready with food. These kids on top of this fuel tanker are being thrown food and juice and water. Moments later this van pulled up. That woman whose name we later learned was Miriam passed out. When the men helping her fell, we helped them carry her to shade and then another woman was brought in. Just now we have another woman who has passed out. It appears from heat exhaustion and she's being tended to by this medic as well. This is becoming a mini clinic here just on the side of the road. Both women were revived. Both said they hope to keep going. Now we're 1500 miles away from the nearest U.S. Border and so far Mexican police and authorities have allowed the migrants to proceed unimpeded but overnight the interior ministry here saying it's going to begin rounding people up unless they apply and register for asylum. He asked these folks, they say it means deportation back to Honduras and they're not willing to take that so we might see a confrontation in the days ahead. Michael. All right, thank you, Matt. Definitely taking an extreme risk.

This transcript has been automatically generated and may not be 100% accurate.