Attorney General Jeff Sessions signaled Monday that victims of domestic abuse and gang violence generally will not qualify for asylum under federal law, a decision that advocates say will affect tens of thousands of foreign nationals seeking safe harbor in the United States.

Sessions’ ruling overturned a 2016 decision by the Justice Department’s Board of Immigration Appeals that said a battered woman from El Salvador was eligible for asylum under federal law. The administrative appeals court is normally the highest authority in the issue, but the attorney general has the power to assign cases to himself and set precedents.

The American Immigration Council, a nonprofit immigrant advocacy group, said Sessions is “taking away a vital lifeline” for victims of severe domestic and gang violence.

“Today’s decision by the Attorney General is yet another attempt to close our doors,” Beth Werlin, executive director of the American Immigration Council, which said legions of mothers and children are fleeing such violence. “Turning our backs on victims of violence and deporting them to grave danger should not be the legacy sought by any administration.”