US Homeland Security Secretary, Kristi Noem, has said she will recommend a travel ban on several countries which she claims are "flooding" the US with criminal activity.

Writing on social media on Monday, Noem said she had met President Donald Trump and decided to suggest "a full travel ban on every damn country that's been flooding our nation with killers, leeches, and entitlement junkies.''

Trump and the Department of Homeland Security (DHS) then shared Noem's post on their respective official social media accounts.

It is not yet clear which countries the proposed travel ban would impact, or when it could begin. The DHS told the BBC it would announce the list soon.

White House press secretary Karoline Leavitt told Fox News on Monday evening that Trump had announced a travel ban several months ago on "third world and failed state" countries, and that Noem's recommendation would "widen" that to encompass more nations.

On 4 June, the White House listed 19 countries, predominantly in Africa, the Middle East and the Caribbean, which would face full or partial immigration restrictions.

Noem's additions would expand that list to about 30 total countries, multiple US officials told CBS News, the BBC's US partner.

Noem's comments come days after two National Guard members were shot in Washington DC last Wednesday. Prior to her comments about a travel ban, Noem wrote on social media that 100,000 Afghan nationals entered the US under the Biden-era Operation Allies Welcome programme, and she said the DHS would overhaul the vetting process.

Officials identified the suspect in the DC shooting as an Afghan national who entered the US in 2021 as part of that programme, which was designed for locals who had worked with American troops during the 20-year US deployment to Afghanistan.

According to emails from last year that were obtained by CBS News, the suspect struggled with his mental health after arriving in the US.

National Guard shooting suspect spent weeks isolated in bedroom, case worker's email said

The Trump administration has intensified its immigration crackdown in the wake of the shooting, which killed Sarah Beckstrom, 20, and seriously injured Andrew Wolfe, 24. West Virginia Governor Patrick Morrisey told reporters on Monday that Mr. Wolfe had responded to nurses with a thumbs-up, but he remained in a serious condition in hospital.

All decisions on asylum requests were also halted after the DC shooting, with US Citizenship and Immigration Services director Joseph Edlow saying it would remain paused "until we can ensure that every alien is vetted and screened to the maximum degree possible".

Edlow has also said he has been asked by Trump to review green cards issued to individuals who migrated to the US from 19 countries.

On Thursday, Trump himself went further, threatening to "permanently pause migration" from all "third world countries." The phrase "third world" is one previously used to describe poorer, developing nations.

In his Thanksgiving social media post, Trump blamed refugees for causing "social dysfunction in America" and vowed to remove "anyone who is not a net asset" to the US.

During his second presidential term, Trump has sought to enact mass deportations of illegal migrants, to cut the annual number of refugee admissions, and to end automatic citizenship rights currently applicable to many born on US territory.

The Afghan Community Coalition of the United States issued a statement after the DC attack, expressing sympathy for the families of the victims, calling for a "comprehensive investigation" and emphasising it was the act of one person. The statement also urged the US government not to delay or suspend Afghan immigration claims.

"Twenty years of Afghan-US partnership must not be forgotten," the coalition's statement said, nodding to the two-decade effort launched by the US in 2001 to overthrow Afghanistan's Taliban rulers and establish security in the country.

The UN has urged the US to observe international agreements on asylum seekers, news agency Reuters reported. (BBC)

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