There's a crazy thing happening along the southern border -- migrants attempting to enter the United States with their dogs are forced to leave them behind, and it's creating a whole other crisis.

FNC reporter Matt Finn is on the ground in Eagle Pass, Texas and joined us Thursday on "TMZ Live" to reveal what he's seeing firsthand ... and how he and other TV crews are getting involved, and taking some of the dogs in themselves.

So many border pups. Anyone want this guy in Eagle Pass? He’s in rough shape but so sweet.

Matt says tons of migrants are trying to cross the border with their dogs, only to be told they can't bring the pups with them to federal processing centers ... resulting in strays roaming the border.

The circumstances leave dogs in need of food, water and shelter ... and Matt says troops with the National Guard are taking care of some of the doggos ... and he and his producer have helped out too.

Border Pupdate 🐾 Today we spotted a dog we took to the vet last year (L) for flea & tick meds. He seems healthy, not scratching & sunbathing by river.

Some dogs have ticks, fleas and worms ... and Matt tells us at least one vet in town is caring for them pro bono.

Matt's seen this tragedy play out before in other areas along the border ... getting a handful of dogs rehomed.

Fact is ... that's just a drop in the bucket, and while some dogs are keeping National Guard troops company while they're stationed at the border ... there's a lot of dogs in need, and a lot more to be done.