JACUMBA HOT SPRINGS, Calif. — A group of migrants from China surrendered to a Border Patrol agent in remote Southern California as gusts of wind drowned the hum of high-voltage power lines, joining others from Ecuador, Brazil, Colombia and elsewhere in a desert campsite with shelters made from tree branches.

Their arrival Wednesday was another sign that agents have become overwhelmed in recent days by asylum-seekers on parts of the U.S. border with Mexico. In tiny Eagle Pass, Texas, nearly 6,000 migrants crossed from Mexico in to the U.S. in two days, prompting authorities to close one of the town’s two official border crossings so those agents could instead help with the influx. Border crossings have closed recently for similar reasons in San Diego and El Paso, Texas.

After a dip in illegal crossings that followed new asylum restrictions in May, President Biden’s administration is again on its heels. Democratic mayors and governors are seeking more relief for hosting asylum-seekers and Republicans are seizing on the issue ahead of 2024 elections.

The Homeland Security Department said Wednesday it would grant Temporary Protected Status to an estimated 472,000 Venezuelans who were in the U.S. on July 31, easing paths to work authorization. That’s in addition to 242,700 Venezuelans who already had qualified for temporary status.

The administration is also sending 800 active-duty military troops to the border, adding to 2,500 National Guard members there. It’s expanding border holding facilities by 3,250 people to nearly 23,000, and extending home surveillance nationwide for families awaiting initial asylum screenings.

The administration renewed pressure – and blame – on Congress, which has long failed to agree on comprehensive changes to the nation’s immigration system. The Biden administration is now asking Congress for $4 billion in emergency funding.

Homeland Security said in a statement that it was “using the limited tools it has available to secure the border and build a safe, orderly, and humane immigration system.”

Theresa Cardinal Brown, the Bipartisan Policy Center’s senior advisor for immigration and border policy, said it’s normal to see a dip in illegal crossings after changes like those imposed in May, but that is usually short-lived once migrants see how things play out.

“People see what happened to the last group of people that tried and they’re like, ‘Oh, well maybe it’s not as harsh as they say,’ ” Brown said.

An increase in families arriving at the border led to unacceptable conditions in two of the busiest Border Patrol sector, a court-appointed monitor reported to a federal court last week. Dr. Paul H. Wise said children as young as 8 years old were separated from parents during processing in South Texas, a practice that has been mainly used for boys 13 to 17.

U.S. Customs and Border Protection said it was reviewing Wise’s report, noting limited, temporary separations may occur during processing for safety reasons but they are nothing like the long-term separations under former President Donald Trump. Wise said even short-term separation can have “lasting, harmful effects.”

In Eagle Pass, a town of 28,000 people, about 2,700 migrants crossed Tuesday and 3,000 Wednesday, according to Maverick County Sheriff Tom Schmerber. Mayor Rolando Salinas declared the city a disaster area on Tuesday.

U.S. authorities closed a bridge and international railway in Eagle Pass on Wednesday to redirect staff. Union Pacific Railroad Co. said Thursday that thousands of rail cars cross the border there daily.

CBP told business leaders they have no estimate of when rail traffic would resume in Eagle Pass or when U.S.-bound commercial truck traffic would reopen at a bridge in El Paso. Traffic slowed at other border crossings.

“All along the border, we’re experiencing large numbers of migrants, so you will see slowdowns and disruptions” at border crossings, said Dennis McKenzie, CBP deputy director for cargo and conveyance security. “It’s all hands on deck.”

In San Diego, a pedestrian crossing has been closed since Sept. 14 to direct staff to an area where migrants from Cameroon to Colombia are waiting between a double-layer border wall in San Diego. Volunteers are handing the migrants food and bottled water while they wait to be processed.

Near Jacumba Hot Springs, a town of less than 1,000 people with a small hotel and general store amid boulder-strewn mountains an hour’s drive east of San Diego, migrants camps began forming last week for the first time since May.

Smugglers drive migrants to a spot in Mexico where the border wall ends. One of three camps in the Jacumba Valley is about a half-hour walk on a gravel road used almost exclusively by border agents. On Wednesday, none had stayed longer than one night, occupying tents that were left behind by others.

The Border Patrol gives migrants colored wristbands marking their arrival date to determine who gets shuttled first to a processing location. Campfires and juniper shrub shield migrants from evening chills. Some climbed atop boulders hoping to get a cellphone signal.

Angel Sisa, 40, left Ecuador’s coastal region with his wife and two children, ages 15 and 13, selling his general store to escape death threats from criminals demanding monthly payments. The Sisa family paid smugglers to take them by plane and bus until they reached a hotel in Tecate, the nearest town in Mexico from the roadside drop where they crossed. They hope to settle in Minneapolis with family members who left Ecuador about a year ago.

Carlos Andres Vasquez, 37, flew from his home country of Colombia to Mexico City as a tourist and paid a smuggler $800 to be driven from Tijuana on a road filled with bumps and potholes before arriving near where they would cross into the U.S.

“They treated like cattle, like animals,” Vasquez said. “They put 20, 18 of us in a van, women and children in front and we went in back.”

He said he and other South Americans walked to the campsite Tuesday under a “very pleasant” Border Patrol agent’s watch. Vasquez, whose father was killed and who left Colombia because of death threats, plans to settle with a friend in Holyoke, Massachusetts, and save money for his wife and children, ages 7 and 2, to join him.