Trump has announced the US will cancel permits allowing nearly 200,000 people from El Salvador to live and work in the country.
The humanitarian programme, Temporary Protected Status (TPS), was granted after a series of earthquakes rocked the Central American country in 2001. Salvadoreans now have until 2019 to leave otherwise they face deportation.
Trump has already removed TPS protections from tens of thousands of Haitians and Nicaraguans.
The programme, which was created in 1990, authorises immigrants from several countries to lawfully live and work in the US regardless of whether they entered the country legally or not. It is only granted to countries affected by armed conflict, environmental disaster, or epidemics.
The US practice of granted citizenship to babies born inside the United States, there are now nearly 200,000 US citizens who were born to parents who now may face deportation.