The US government has halted immigration applications for citizens from 19 nations including Afghanistan, Yemen and Haiti, an official memorandum said Tuesday, deepening the nation’s sweeping crackdown on migration.

Authorities paused green card and citizenship processing, according to the memo, for people from countries already subject to travel restrictions announced in June by President Donald Trump.

Those 19 nations also include Venezuela, Sudan and Somalia.

Senior US officials have signaled in recent days they would starkly tighten restrictions on immigration, a move fueled by the shooting of two National Guard soldiers last week.

The main suspect in the shooting, which killed one, is an Afghan national.

The man, who on Tuesday pleaded not guilty to murder charges, entered the United States during mass evacuations as foreign forces withdrew from Afghanistan in 2021.

“USCIS plays an instrumental role in preventing terrorists from seeking safe haven in the United States and ensuring that USCIS’ screening and vetting and adjudications prioritize the safety of the American people and uphold all US laws,” the memorandum said, referring to the US Citizenship and Immigration Services.

The memorandum said the US had recently seen “what a lack of screening, vetting, and prioritizing expedient adjudications can do to the American people,” citing the suspected shooter in last week’s attack as an example.

Trump, who campaigned for the White House on a pledge to deport millions of undocumented migrants, said on November 26, following the shooting that he planned to “permanently pause migration from all Third World Countries to allow the US system to fully recover.”

US Homeland Security chief Kristi Noem also urged on Monday an expansion of the list of countries covered by the June travel restrictions.

“I just met with the President. I am recommending a full travel ban on every damn country that’s been flooding our nation with killers, leeches, and entitlement junkies,” she said on X, without naming which countries she believed should be included.

The travel restrictions currently also apply to Burundi, Chad, Republic of Congo, Cuba, Equatorial Guinea, Eritrea, Iran, Laos, Libya, Myanmar, Sierra Leone, Togo, and Turkmenistan.

Also on Tuesday, US media reported federal authorities planned in coming days to launch a major immigration enforcement operation in Minnesota that would focus on Somali immigrants, sparking pushback from local leaders who said state police would not cooperate.

“Our values and our commitments to the Somali community, to every community of immigrants and people in our city is rock solid and will be unwavering,” said Minneapolis mayor Jacob Frey.