US Homeland Security chief Kristi Noem ordered the suspension of the diversity visa lottery progamme on Thursday after saying it was used by the suspect in a mass shooting at Brown University.

“The Brown University shooter, Claudio Manuel Neves Valente, entered the United States through the diversity lottery immigrant visa programme (DV1) in 2017 and was granted a green card,” Noem wrote on social media.

“At president Trump’s direction, I am immediately directing US Citizenship and Immigration Services (USCIS) to pause the DV1 programme to ensure no more Americans are harmed by this disastrous programme,“ she said.

According to the Associated Press, the diversity visa programme makes up to 50,000 green cards available each year by lottery to people from countries that are little represented in the US, many of them in Africa.

The lottery was created by Congress, and the move is almost certain to invite legal challenges, AP reported.

Officials said earlier that the suspect was dead as investigators said he also killed a Massachusetts Institute of Technology professor two days after the rampage at Brown.

He had been a PhD student in physics who was familiar with the building where the shooting took place, officials said.

Providence police Chief Oscar Perez and Rhode Island Attorney General Peter Neronha, speaking at a Thursday night press conference, said that Valente took his own life and investigators believe he acted alone.