AnAfghan national has been accused of shooting two West Virginia National Guard members just blocks from the White House in a brazen act of violence at a time when the presence of troops in the nation's capital and other cities around the US has become a political flashpoint.

Jeanine Pirro, the US attorney for the District of Columbia, said at a Thursday (early Friday AEDT) news briefing that the guard members shot were Specialist Sarah Beckstrom, 20, and Staff Sergeant Andrew Wolfe, 24. The guard members were hospitalised in critical condition after Wednesday afternoon's shooting.

Pirro said that the suspect, Rahmanullah Lakanwal, drove across the country to launch an"ambush-style" attack with a.357 Smith & Wesson revolver.

The suspect currently faces charges of assault with intent to kill while armed and possession of a firearm during a crime of violence. Pirro said that"it's too soon to say" what the suspect's motives were.

The charges could be upgraded, Pirro said.

"We are praying that they survive and that the highest charge will not have to be murder in the first degree," she said.

"But make no mistake, if they do not, that will certainly be the charge."

The rare shooting of National Guard members on American soil, on the day before Thanksgiving, comes amid court fights and a broader public policy debate about the Trump administration's use of the military to combat what officials cast as an out-of-control crime problem.

The Trump administration quickly ordered 500 more National Guard members to Washington.

The suspect who was in custody also was shot and had wounds that were not believed to be life-threatening, according to a law enforcement official who was not authorised to discuss the matter publicly and spoke to AP on condition of anonymity.

Attack being investigated as terrorist act

FBI Director Kash Patel said the shooting is being investigated as an act of terrorism. Agents have served a series of search warrants, with Patel calling it a"coast-to-coast investigation".

The shot guard members had been sworn in less than 24 hours before they were attacked

"We have been in constant contact with their families and have provided them with every resource needed during this difficult time," Pirro said.

Washington Mayor Muriel Bowser interpreted the shooting as a direct assault on America itself, rather than specifically on Trump's policies.

"Somebody drove across the country and came to Washington, DC, to attack America," Bower said.

"That person will be prosecuted to the full extent of the law."

Suspect worked with CIA during Afghanistan War

The 29-year-old suspect, an Afghan national, entered the US in 2021 through Operation Allies Welcome, a Biden administration program that evacuated and resettled tens of thousands of Afghans after the US withdrawal from the country, officials said.

The initiative brought roughly 76,000 people to the US, many of whom had worked alongside US troops and diplomats as interpreters and translators.

It has since faced intense scrutiny from Trump and his allies, congressional Republicans and some government watchdogs over gaps in the vetting process and the speed of admissions, even as advocates say it offered a lifeline to people at risk of Taliban reprisals.

Lakamal has been living in Bellingham, Washington, about 127 kilometres north of Seattle, with his wife and five children, said his former landlord, Kristina Widman.

Prior to his 2021 arrival in the United States, the suspect worked with the US government, including the CIA,"as a member of a partner force in Kandahar," John Ratcliffe, the spy agency's director, said in a statement. He did not specify what work Lakamal did, but said the relationship"ended shortly following the chaotic evacuation" of US service members from Afghanistan.

Kandahar in southern Afghanistan is in the Taliban heartland of the country. It saw fierce fighting between the Taliban and NATO forces after the US-led invasion in 2001 following the al-Qaeda attacks on September 11. The CIA relied on Afghan staff for translation, administrative and frontline fighting with their own paramilitary officers in the war.

Wednesday night, in a video message released on social media, US President Donald Trump called for the reinvestigation of all Afghan refugees who entered under the Biden administration.

"If they can't love our country, we don't want them," he said, adding that the shooting was"a crime against our entire nation".

Jeffery Carroll, an executive assistant DC police chief, said on Wednesday investigators had no information on a motive. He said the assailant"came around the corner" and immediately started firing at the troops, citing video reviewed by investigators.

"This was a targeted shooting," Mayor Bowser said.

Troops held down the shooter

The shooting happened roughly two blocks north-west of the White House near a metro station. Hearing gunfire, other troops in the area ran over and held down the gunman after he was shot, Carroll said.

"It appears to be a lone gunman that raised a firearm and ambushed these members of the National Guard," Carroll said, adding that it was not clear whether one of the guard members or a law enforcement officer shot the suspect.

"At this point, we have no other suspects," Carroll said at a news conference.

At least one of the guard members exchanged gunfire with the shooter, said another law enforcement official who was not authorised to discuss the matter publicly and spoke on condition of anonymity.

Social media video shared in the immediate aftermath showed first responders performing CPR on one of the troops and treating the other on a sidewalk covered in broken glass.