SAN DIEGO (AP) — The downcast faces on computer screens are 1,500 miles away at a Border Patrol station in McAllen, Texas: a 20-year old Honduran woman arrested rafting across the Rio Grande and a 23-year-old man caught under similar circumstances.

Four agents wearing headsets reel through a list of personal questions, spending up to an hour on each adult and even longer on children. On an average day, hundreds of migrants are questioned on camera by agents in San Diego and other stations on the U.S.-Mexico border.

The long-distance interviews — introduced last year in El Paso, Texas, and extended to California — are a response to the dramatic increase of Central Americans crossing the border in Texas that also has flooded immigration facilities with hundreds of women and children. The Border Patrol does not have the staff to process all the immigrants crossing in the Rio Grande Valley, but faraway colleagues have time to spare.

The remote video processing reveals a perpetual predicament that has long bedeviled the Border Patrol. Many agents wind up stationed in places where crossing activity is slowest because the Border Patrol struggles to keep up with constantly shifting migration patterns.

One example of the staffing mismatch: the roughly 2,500 agents in the San Diego sector arrested 97 immigrants illegally crossing the border on June 14, according to an internal document reviewed by The Associated Press. On the same day, the roughly 3,200 agents in the Rio Grande Valley made 1,422 arrests.

President Barack Obama will ask Congress for more than $2 billion to respond to the flood of immigrants illegally entering the U.S. through the Rio Grande Valley and for new powers to deal with returning unaccompanied children, a White House official said Saturday. A letter will be sent to Congress on Monday, said the official who was not authorized to speak by name and discussed the requests on condition of anonymity. The exact amount and how it will be spent will come after Congress returns from recess on July 7. Whether any funds will go toward border staffing is unknown.

In San Diego, the video processing is a welcome change of pace. Arrests are at 45-year lows and many agents go entire shifts without finding anyone. Cesar Rodriguez, who joined the Border Patrol in 2010, said eight hours fly by since he gave up his assignment watching a stretch of scrub-covered hills east of San Diego and took on a new assignment to process the immigrants via video.

“If there’s nothing going on, what are you going to do? You’re just staring at the fence,” Rodriguez said in his new office, whose parking lot offers sweeping views of hillside homes in Tijuana, Mexico.

A few feet away, Victor Nunez says he interviewed a woman carrying a 4-month-old child and spent his last shift working on a group of 93 people that crossed the Rio Grande at once. Such activity was unheard of on his overnight shift patrolling the quiet mountains near San Diego.

“I feel like we’re helping out our agents,” said Nunez, who joined the Border Patrol in 2011. “It’s a big problem going on there.”

The McAllen station is designed to hold a few hundred people, but often teems with more than 1,000 who spill into hallways and outside. Migrants have been sent to stations in quieter parts of Texas, and they were overwhelmed. Overcrowding at the Laredo station prompted a visit from the fire marshal last month.

The shift to the Rio Grande Valley is part of a long-running trend where immigrants and smugglers change crossing locations faster than the government responds.

San Diego was the hot spot until the mid-1990s, when 1,000 agents were added there. After traffic moved to Arizona, staffing in Tucson ballooned under President George W. Bush, who doubled the Border Patrol close to its current size of more than 21,000 agents.

Some warn against bulking up in South Texas because smuggling routes will inevitably change along the 1,954-mile border.

“They don’t want to transfer a mass amount of agents and open a gap somewhere else where we have control,” said David Aguilar, the Border Patrol chief from 2004 to 2010.

Forced transfers must be negotiated with the National Border Patrol Council, the union which represents agents, and have not happened on a large scale.

The Border Patrol can move agents for 35 days — longer by mutual agreement — but those temporary assignments are expensive. More than 100 agents were sent to Rio Grande Valley this spring for short stays.

Voluntary transfers were an option but have not been used widely in South Texas. The Border Patrol began a campaign about 10 years ago, partly aimed at boosting morale, to offer more transfers if agents moved themselves. And, as agents quit or retire, the vast majority of new hires who replace them are now assigned to Rio Grande Valley.

The Border Patrol introduced video processing in El Paso in April 2013 to address the surge in Rio Grande Valley, where most border crossers are from Honduras, El Salvador and Guatemala and many are unaccompanied children. It expanded the processing to El Centro, California, in March, and to San Diego last month.

Between 230 and 500 people have been processed by video each day since it was introduced last year, but lack of detention space in Rio Grande Valley recently prompted authorities to fly migrants to El Paso and Arizona for processing, said Jackie Wasiluk, a spokeswoman for the Border Patrol’s parent agency, Customs and Border Protection. The agency said Friday that it will also fly migrants to California for processing.

Costs are not an issue with video processing. Headsets and cameras are $70 apiece, and it’s a small sacrifice to supervisors.

Agents use a long questionnaire that aims to establish identity — where they lived, where they went to school, where they went to church. Most migrants don’t have identification, so U.S. authorities must convince consulates to issue passports. Otherwise, they can’t be deported.

Throughout their shifts, agents trade instant messages with counterparts in Rio Grande Valley.

“If you have time, can you adjust the camera? It was too high. Ready for another case if you have one,” typed Jake Garcia, a San Diego agent for five years.

His counterpart was talking to a group of migrants. Garcia swirled his chair for something rare in his new role: He took a break.

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Associated Press writer Christopher Sherman in McAllen, Texas, contributed to this report.