President Donald Trump signed an executive order Wednesday to bar undocumented migrants from accessing public benefits, even though they’re already denied most federally funded programs—his latest move to tamp down on illegal immigration, though it wasn’t immediately clear which initiatives would be impacted.

The number of detainees in ICE custody without a criminal conviction or pending criminal charges increased by more than 1,800 in February.

The leadership change comes as the president aims to make good on a promise of mass deportations and arrests of undocumented immigrants across the United States.