Trump previously said the shooting underlined a major national security threat and promised to take steps to remove any foreigner “from any country who does not belong here”.
On Wednesday, the US suspended processing all immigration requests from Afghans, saying the decision was made pending a review of “security and vetting protocols”.
Then on Thursday, the US Citizenship and Immigration Services said it would re-examine green cards issued to individuals who immigrated to the US from 19 countries.
When asked by the BBC which countries were on the list, the agency pointed to a June proclamation by the White House that included Afghanistan, Cuba, Haiti, Iran, Somalia and Venezuela.
There were no further details about what the re-examination would look like.
Trump’s latest post on Thursday night went further, pledging to “end all federal benefits and subsidies to noncitizens”.
The flurry of announcements follow reports that the suspect in Washington DC shooting came to the US in 2021 under a programme that offered special immigration protections to Afghans in the wake of the US withdrawal from Afghanistan.
Officials said Rahmanullah Lakanwa once worked alongside the CIA in Afghanistan and helped guard US forces at Kabul airport during evacuations, a former military commander who served alongside him told the BBC’s Afghan Service.