US Citizenship and Immigration Services says it has stopped processing all immigration requests relating to Afghan nationals.
"Effective immediately, processing of all immigration requests relating to Afghan nationals is stopped indefinitely pending further review of security and vetting protocols," the department said in a statement.
The decision comes hours after US President Donald Trump said he was confident the suspect behind the shooting of two National Guard soldiers in Washington was from Afghanistan.
The president called the shooting "an act of terror" and called for the re-examining of "every single alien who has entered our country from Afghanistan under Biden".
Mr Trump said the "heinous assault" on two National Guard members near the White House proved that lax migration policies were "the single greatest national security threat facing our nation".
"No country can tolerate such a risk to our very survival," he said.
His remarks, released in a video on social media, underscore his intention to reshape the country's immigration system and increase scrutiny of immigrants already in the US.
The suspect entered the US in September 2021 after the chaotic collapse of the government in Kabul, when Americans were frantically evacuating people as the Taliban took control.
The 29-year-old was part of Operation Allies Welcome, the Biden-era program that resettled tens of thousands of Afghans after the US withdrawal from the country, officials said.
The initiative brought roughly 76,000 Afghans to the US, many of whom had worked alongside American troops and diplomats as interpreters and translators.
Mr Trump described Afghanistan as "a hellhole on earth" he said his administration would review everyone who entered from the country during Mr Biden's tenure.
Supporters of Afghan evacuees said they feared that people who escaped danger from the Taliban would now face renewed suspicion and scrutiny.
"I don't want people to leverage this tragedy into a political ploy," #AfghanEvac president Shawn VanDiver said.
He said Wednesday's shooting should not shed a negative light on the tens of thousands of Afghan nationals who had gone through the various legal pathways to resettling in the US, as well as those already in the pipeline.
Vice-President JD Vance criticised Mr Biden for "opening the floodgate to unvetted Afghan refugees," adding that "they shouldn't have been in our country".
"Already some voices in corporate media chirp that our immigration policies are too harsh," he said on social media.
"Tonight is a reminder of why they're wrong."
ABC/Wires
