As the U.S. border crisis continues, more foreign nationals are finding their way through Mexico to the U.S., undermining the Biden administration's effort to stop illegal immigration by addressing the root causes of why people leave Central America.

Apprehensions of migrants from Ecuador, Brazil, Venezuela and Nicaragua are all up more than 200%, irrespective of U.S. taxpayer investments in Honduras, Guatemala and El Salvador. President Biden has pledged $4 billion in U.S. tax dollars to address the root causes of immigration from Northern Triangle countries, including climate change, poverty and violence. 

Last week, scores of Brazilians and Cubans entered through a gap in the fence in Arizona. Haitians immigrants have taken over parts of a tent encampment in Tijuana. Romanians have established a pathway into San Diego. Venezuelans are more likely to enter the U.S. in Del Rio, Texas, than El Salvadorans. The number of Cuban migrant apprehensions increased 70%.

People surround a car as it arrives carrying food donations at a makeshift camp for migrants seeking asylum in the United States at the border crossing Friday, March 12, 2021, in Tijuana, Mexico. (AP Photo/Gregory Bull)

People surround a car as it arrives carrying food donations at a makeshift camp for migrants seeking asylum in the United States at the border crossing Friday, March 12, 2021, in Tijuana, Mexico. (AP Photo/Gregory Bull)

"Cuba is horrible today," said former Havana resident Laura Carrazana, moments after being apprehended in San Luis, a border town in southwest Arizona. "I have no food. I have a child. I have no work to eat, so I need to come here. It is dangerous I know, but I do it. I made it."

Unlike most Central Americans, who either walk or take a series of buses to the border, many foreign nationals fly to the border. The U.S. is negotiating with Mexico to close one loophole: a list of 68 nations from which travelers do not need a visa to enter Mexico. That list includes Ecuador and Brazil, and it allows immigrants to fly into those countries from the Caribbean, Asia and Africa, to hop-scotch to the U.S., where they would otherwise be stopped.

"They're flying in to locations in Mexico, flying up to locations at the border and then being transported by some kind of bus line or a cab company or personal vehicles to the border," said Yuma Chief Patrol Agent Chris Clem. "And they're literally walking a couple of hundred yards across the border."

GOP REP WARNS ‘NO OPERATIONAL CONTROL’ OF BORDER AFTER SEEING MIGRANTS STREAM IN, BOARD FLIGHTS

Sixty-three percent of some 22,000 Brazilians who entered the U.S. this year came through Yuma. Yet the trip, while more comfortable than walking hundreds of miles, is not without danger.

The Border Patrol released surveillance video of border bandits robbing immigrants at gunpoint as they cross into the U.S. in San Luis last month. The video shows the bandits raising a handgun until the migrants hand over money. Only then are they allowed to cross.

 "It's a 365-day-a-year profit for them," says Clem.

CLICK HERE TO GET THE FOX NEWS APP

While many critics blame the Biden administration's lax enforcement policy for encouraging migrants to come, others cite lack of a legal pathway for highly motivated foreign nationals who want to  live and work in the U.S.

"We're seeing people make perfectly natural decisions to say, ‘OK, where are there jobs, where can I find work?’ And in the U.S., people can find work," says Ali Noorani, director of the National Immigration Forum. "And if we really want to stem these numbers, we've got to stand these economies back up in Central America and South America and we have to build out a functioning legal immigration system here in the U.S."