Immigration advocates and former immigration judges denounced Attorney General Jeff Sessions’ ruling this week restricting asylum for people fleeing domestic or gang violence, saying the decision could cost lives and endanger tens of thousands of people.

One lawyer working with immigrants, Kathryn Shepherd, called the decision "essentially a death sentence to potentially thousands of people fleeing harm.”

On Monday, Sessions reversed an immigration court’s ruling that granted asylum to a woman from El Salvador who said her husband had repeatedly abused her physically, sexually and emotionally. Sessions wrote that “generally” claims on domestic and gang violence will no longer qualify for asylum.

Only 20 percent of asylum applications were granted last fiscal year, according to the U.S. Citizenship and Immigration Services, which handles some asylum cases.

Now, advocates fear that even more asylum seekers from Central America and Mexico will have their claims denied, said Shepherd, the national advocacy counsel for the Immigration Justice campaign at the American Immigration Council, an advocacy group for immigrants.

“It is making it nearly impossible,” she said.

Sessions' decision has also "created a lot of anguish" for the Salvadoran woman at the center of the case, one of the woman's lawyers said Tuesday in vowing to fight the ruling.

"This is obviously very distressing," said Karen Musalo, who is helping to represent the Salvadoran woman, known as A.B. in court papers.

Musalo, who is co-counsel on the case, said A.B. has endured a "roller coaster of emotions" since she suffered the alleged abuse in El Salvador and fled to the U.S. four years ago. She was initially denied asylum by an immigration judge, but an immigration board of appeals reversed that and granted her asylum. That's when Sessions stepped in to review the case.

Musalo said she and the team of lawyers representing A.B. are also looking to take on other cases to challenge Sessions' ruling, including cases where asylum has been denied.

Under U.S. and international law, a person may seek asylum based on persecution or a well-founded fear of future persecution because of race, religion, nationality, political opinion or membership in a particular social group.

While asylum outcomes can vary widely based on the judges deciding the cases, domestic violence victims have recently sometimes been considered a "social group" that qualifies for asylum. In 2014, an immigration court recognized "married women in Guatemala who are unable to leave their relationship" as such a social group, a ruling that Sessions has now overturned.

Sessions said in his ruling that the criteria for asylum had been widened too far and should not include victims of “private violence.”

“The asylum statute does not provide redress for all misfortune," Sessions wrote in the decision. "The mere fact that a country may have problems effectively policing certain crimes — such as domestic violence or gang violence — or that certain populations are more likely to be victims of crime cannot itself establish an asylum claim."

Unlike the 2014 Guatemala domestic violence case, there was never a single precedent-setting case that allowed for asylum claims based on gang violence. Rather, there were a collection of cases in which people claiming asylum faced multiple threats, including gang violence, and won the ability to stay in the U.S., said Michael Kagan, a professor and director of the immigration clinic at University of Nevada, Las Vegas’ law school.

He said children have successfully claimed asylum after gangs threatened to kill them as revenge against their parents.

"Those cases are not easy to win but they are winnable," he said, but now they will be nearly impossible.

Sessions' decision raises fears that people fleeing deadly violence could be turned away or deported "and we will never even know about them because they will not get a hearing in court," he said.

A group of 15 former immigration judges and former members of the Board of Immigration Appeals said in a letter that they considered Sessions’ decision “an affront to the rule of law.”

“For reasons understood only by himself, the attorney general today erased an important legal development that was universally agreed to be correct,” they wrote.

The group said the immigration board's acknowledgment of domestic violence victims as people who may qualify for asylum was “the culmination of a 15-year process through the immigration courts” and the immigration board.

They said they hoped appellate courts or Congress reverse the action.

Sessions has argued that the asylum system is being abused and "was never meant to alleviate all problems, even serious problems that people face every day all over the world."

The government does not track the specific reasons people are granted asylum, so there are no numbers available on cases involving domestic and gang violence claims.

Asylum claims in general have grown more common. Before 2013, about one out of every 100 immigrants sought asylum in the U.S., according to U.S. Citizenship and Immigration Services. Currently, one out of every 10 do so.

In all, the number of people who claimed asylum at the U.S. border or after being caught in the country illegally rose from 13,000 in fiscal year 2010 to 119,000 in fiscal year 2017, the group said.

Michelle Brané, director of the Migrants Rights and Justice Program at the advocacy group Women’s Refugee Commission, said Sessions' decision was “just another step in the long list of actions this administration has taken to undermine any way for immigrants to come to this country.” She also noted his decision to seek to prosecute 100 percent of immigrants crossing the border illegally, resulting in family separations.

Kagan said that the case of A.B., the Salvadoran woman whose case Sessions decided this week, could lead to years of court battles without clear resolution.

“This is likely just to muddy the waters in the courts and lead to years of litigation all over the country,” he said.

He said he was concerned for the children in his clinic whose asylum claims are still being processed, including those who have seen family members killed, as well as girls who had been raped by gang members and gotten pregnant and children who were being recruited by gangs.

"Their stories are just absolutely horrendous in terms of the lives and families disrupted," he said. "A lot of our clients or their parents ran away when they really had tried everything else."