HOUSTON (AP) — After being denied U.S. asylum in Texas and returned to a squalid camp in Mexico, a mother from El Salvador chose to send her three children back across the border alone. Now, those children face deportation, even though their father lives in Maryland and is eager to take them in, according to attorneys.

Lawyers for the children sued the U.S. government Tuesday demanding that the children be released from a government facility and allowed to seek asylum.

Their mother remains in Matamoros, Mexico, where an estimated 2,000 people live in a squalid tent camp, waiting for their court hearings a short distance away in Brownsville, Texas.

Many parents at the camp have made the same choice. According to the U.S. Department of Health and Human Services, 498 children in its custody have said their family is in Mexico.

In the lawsuit filed in federal court in Washington, D.C., the CAIR Coalition and Justice Action Council argue that the children deserve a new court hearing because they are now considered “unaccompanied” children under government rules.

The Associated Press is withholding the names of the mother and her children because they fear being targeted by MS-13 if forced to return to El Salvador.

According to the lawsuit, the mother and father were active in their local church in El Salvador and frequently evangelized to others. They believe their ministry drew the attention of MS-13, the violent transnational gang. Gang members attacked the father and eventually threatened his life, leading the family to flee.

They lived in Mexico for two years, then moved back to El Salvador, going from town to town, the lawsuit says. But they concluded last year that they would have to try to enter the U.S.

The father and his second eldest daughter went first, arriving in the U.S. in June 2019 and settling in Maryland after they were released by border agents.

The mother and three of their children — daughters now aged 16 and 14, and a 9-year-old son — left later and arrived at the U.S.-Mexico border in September. By then, the U.S. had implemented its “Remain in Mexico” program in South Texas, under which more than 50,000 people have been sent back across the border with court dates sometimes months away.

The mother and her three children were sent to Matamoros under the program.

In January, a judge in Brownsville denied their asylum claim and the family returned to the camp.

At the camp, someone grabbed the 16-year-old daughter and tried to assault her. Another person beat the 9-year-old boy and took money he had to buy food. They had seen kidnappings and extortion attempts, and once observed a corpse floating in the nearby Rio Grande.

So the mother sent her three children across the border alone in January.

The Department of Health and Human Services has declined to release the three children, so their father goes to a facility in Crofton, Maryland, to see them.

He says he is certain that if they are deported, they would be killed.

“My only purpose was to save my family,” he said.

Even if the children win their case in U.S. courts, the mother may have no way of entering the country herself. According to her lawyers, she has missed a deadline to file an appeal.

The mom said she would be happy regardless.

“A mother wants the best for her children,” she said. “Nothing can compare to a mother's love.”