SAN SALVADOR, El Salvador — Though his future may be in doubt, Attorney General Jeff Sessions forged ahead Thursday with a tough-on-crime agenda that once endeared him to President Trump, opening a mission in El Salvador to step up international cooperation against the violent street gang MS-13.

Sessions arrived in San Salvador for a series of meetings with law enforcement officials about a transnational antigang task force aimed against MS-13. He planned to meet his Salvadoran counterpart as well as an former gang member, and tour a prison.

Back in Washington, lawmakers sized up the fallout over a week of public scorn heaped on Sessions by his boss, Trump, even as the White House suggested the president prefers that his attorney general stay on the job. Senator Lindsey Graham, Republican from South Carolina, said Thursday that there would be ‘‘holy hell’’ to pay if Trump were to fire Sessions, a former Alabama senator and early Trump supporter.

As the Trump administration tries to build support for its crackdown on illegal immigration, it has increasingly tried to make the gang with Central American ties the face of the problem. Recent killings tied to its members have stoked the US debate on immigration.

Trump praised Sessions when Sessions announced his mission to eradicate the gang in April. But the attorney general has since fallen out of favor with his onetime political ally.

MS-13 is an international criminal enterprise with tens of thousands of members in several Central American countries and many US states. The gang originated in immigrant communities in Los Angeles in the 1980s then entrenched itself in Central America when its leaders were deported.

Both Trump and Sessions have blamed Obama-era border policies for allowing the gang’s ranks to flourish in the United States, though the Obama administration took unprecedented steps to target the gang’s finances.