The U.S. Citizenship and Immigration Services said it would immediately stop the processing of all immigration requests relating to Afghan nationals after an Afghan man was arrested in connection to a Washington DC shooting that left two National Guard members fighting for their lives.

"Effective immediately, processing of all immigration requests relating to Afghan nationals is stopped indefinitely pending further review of security and vetting protocols," USCIS said in a post on social media platform X, previously known as Twitter.

"The protection and safety of our homeland and of the American people remains our singular focus and mission," the agency said.

Afghan national Rahmanullah Lakanwa has been named as the suspected shooter of two National Defense guards on Wednesday, November 26.

The pair on duty when the targeted attack took place and are both in critical condition in hospital according to FBI director Kash Patel.

The 29-year-old came to the US in September 2021 through Operation Allies Welcome under the Biden administration.

The programme evacuated and resettled tens of thousands of Afghans after the US withdrew from the country following an almost 20-year-fight against the Taliban.

A relative of Lakanwa told NBC News that the suspect had served alongside US Special Forces troops in Afghanistan before moving to the US. They revealed that Lakanwal had spent 10 years in the Afghan Army, with part of that time stationed at a base in Kandahar.

Addressing the nation on the attack, US President Donald Trump blamed the Biden administration.

"He was flown in by the Biden administration in September 2021 on those infamous flights that everybody was talking about. Nobody knew who was coming in, nobody knew anything about it," Trump said.