WATCH: More Than 1,000 Migrants Cross Border Into El Paso Overnight

A massive caravan of more than 1,000 migrants crossed the southern border of the U.S. into El Paso, Texas, on Sunday night.

Video posted to Twitter by Fox News correspondent Bill Melugin showed the group wading across the Rio Grande River from Mexico.

“A huge migrant caravan of over 1,000 people crossed illegally into El Paso, TX last night, making it the largest single group we have ever seen,” Melugin tweeted Monday morning. “The city of El Paso reports Border Patrol now has over 5,000 in custody & has released hundreds to city streets.”

BREAKING: A huge migrant caravan of over 1,000 people crossed illegally into El Paso, TX last night, making it the largest single group we have ever seen. The city of El Paso reports Border Patrol now has over 5,000 in custody & has released hundreds to city streets. @FoxNews pic.twitter.com/ewUQX757Lt

— Bill Melugin (@BillFOXLA) December 12, 2022

According to Melugin, the migrants could be traced to a series of buses that recently traveled to Ciudad Juarez, a Mexican city on the river just south of El Paso.

“Before this mass of migrants crossed, Mexican police escorted nearly 20 buses full of migrants into Ciudad Juarez, the MX city across from El Paso, and released them at multiple NGOs [Non-Governmental Organizations]. The migrants then walked from the NGOs to the river, & crossed illegally into El Paso,” he wrote on Sunday.

Before this mass of migrants crossed, Mexican police escorted nearly 20 buses full of migrants into Ciudad Juarez, the MX city across from El Paso, and released them at multiple NGOs. The migrants then walked from the NGOs to the river, & crossed illegally into El Paso. @FoxNews pic.twitter.com/KgE2HUVbej

— Bill Melugin (@BillFOXLA) December 12, 2022

El Paso Matters reported that the migrants were part of a caravan stopped in Chihuahua, Mexico, on Thursday, more than 200 miles from the U.S. border, before being allowed to proceed.

“The migratory flow cannot be opened, and there is no support for migrants in Ciudad Juárez. This affects the people of Juárez,” Chihuahua Gov. Maru Campos told the outlet.

“Right now, between 1,200 to 1,500 migrants are coming through Jimenez in the south of the state, guarded by the federal government. There is no more space in the shelters. If they arrive in Ciudad Juárez, we will look out for them. But we are urgently calling on the federal government for help,” Campos said.

Developing: More than 1,000 migrants have begun crossing from Juarez into El Paso, one of the largest mass crossings ever. Video from @CorrieBoudreaux 1/ pic.twitter.com/vKGIe2dqkF

— El Paso Matters (@elpasomatters) December 12, 2022

The concerning number of migrants recently entering El Paso comes as many predict unlawful crossings are about to worsen. Title 42, a Trump-era policy that allows agents to turn away migrants due to COVID concerns, is set to expire on December 21.

Fifteen state attorneys general petitioned a federal judge to keep the program alive.

“Because invalidation of the Title 42 Orders will directly harm the States, they now seek to intervene to offer a defense of the Title 42 policy so that its validity can be resolved on the merits, rather than through strategic surrender,” the court filing said.

“[B]order states like Arizona and Texas will face increased migrant flows and increased releases of aliens if the Title 42 process is terminated. Those aliens will flow to other States, too,” it added.

In May, Homeland Security Secretary Alejandro Mayorkas admitted that the end of Title 42 could result in up to 18,000 migrant crossings per day. If so, the U.S. could see more than a half-million illegal immigrants per month entering the country.

The same month, attorneys general from 24 states, led by Louisiana, filed a lawsuit claiming that rescinding Title 42 would violate federal regulatory procedures, The Daily Wire reported.