The FBI is probing the motives of a man who opened fire on a group of Republican congressmen as they were practising for a charity baseball game against a team of Democrats – an apparently deliberate attack on some of the most powerful politicians in the country.

The congressmen and their aides who came under fire from a semi-automatic weapon at an early morning sports session on the outskirts of Washington DC told dramatic accounts of how they scrambled for safety behind the field’s dugout, with at least one congressman and several aides being hit by bullets. The suspected gunman – identified as James Hodgkinson – was wounded after a firefight with police, before dying in hospital from his injuries.

Congressman Steve Scalise, an ally of President Trump and the Republican Whip in the House, was shot in the hip. He was able to drag himself to safety, as the politicians’ security officers, members of the United States Capitol Police, returned fire with their pistols. The Washington hospital where Mr Scalise was taken to said the Representative had undergone surgery, but was in a "critical" condition.

“I was out there waiting to get ready when I heard shots. There must have been 50 to 100 shots fired,” Congressman Mo Brooks said. “Then I heard Steve Scalise at 2nd Base. He screams. There is a semi-automatic.”

Mr Brooks said he was able to scramble over to Mr Scalise. Mr Brooks said as Mr Scalise dragged himself towards the dug out to seek cover, he took off his belt and was able to use it as a tourniquet to help a member of the congressional staff who had also been shot.

In all, five people were taken to area hospitals, including the suspect, Alexandria police said. Matthew Mika, a lobbyist for Arkansas-based Tyson Foods Inc and former staff member for two former Republican representatives, was shot in the chest. Zack Barth, a staff member for Texas Representative Roger Williams was also injured. Two Capitol Hill police officers – David Bailey and Crystal Griner – were also injured.

“Everyone on that field is a public servant,” Mr Trump said from the White House as he called for unity. “Their sacrifice makes democracy possible.”

Virginia Shooting Show all 20 1 /20 Virginia Shooting Virginia Shooting House Majority Whip Steve Scalise of Louisiana and others were shot Wednesday at a congressional baseball practice, officials said AP Virginia Shooting Police and emergency personnel are seen near the scene where House Majority Whip Steve Scalise was shot during a Congressional baseball practice in Alexandria, Va AP Virginia Shooting A man receives medical attention from first responders on the scene following a shooting in Alexandria, Virginia, US EPA Virginia Shooting The Republican House majority whip Steve Scalise and at least four others have been shot shot at a congressional baseball game practice session, according to media report EPA Virginia Shooting Police close a street near the scene of a shooting in Alexandria, Virginia EPA Virginia Shooting Police close a street near the scene of a shooting in Alexandria, Virginia, USA EPA Virginia Shooting The Republican House majority whip Steve Scalise and at least four others have been shot shot at a congressional baseball game practice session, according to media reports EPA Virginia Shooting First responders on the scene following a shooting in Alexandria, Virginia, USA EPA Virginia Shooting Alexandria, Va. Police Chief Michael Brown speaks about the shooting in Alexandria, Va AP Virginia Shooting Rep. Jack Bergman, R-Mich. talks on the phone while walking past a damaged vehicle at a shooting scene where House Majority Whip Steve Scalise of La. was shot at a Congressional baseball practice AP Virginia Shooting A Capitol Hill Police officer walks past an automobile with the driver's window damaged at the scene of a shooting in Alexandria, Va AP Virginia Shooting Rep. Chuck Fleischmann, R-Tenn. is seen near the scene of a shooting in Alexandria, Va AP Virginia Shooting A Capitol Hill Police officer stands his post at the entrance to the House of Representatives on Capitol Hill in Washington AP Virginia Shooting Law enforcement officers investigate the scene of a shooting near a baseball field in Alexandria, Va AP Virginia Shooting An Alexandria, Va. police officer tapes off an area near the YMCA after a shooting in Alexandria, Va AP Virginia Shooting Sen. Jeff Flake, R-Ariz. walks toward media gathered at the scene of a shooting at a baseball field in Alexandria, Va AP Virginia Shooting The baseball field that is the scene of a shooting in Alexandria, Va AP Virginia Shooting Law enforcement officers gather near a shooting scene at baseball field in Alexandria, Va AP Virginia Shooting Rep. Joe Barton, R-Texas and other members of the Republican Congressional softball team, stand behind police tape of the scene of a multiple shooting in Alexandria, Va AP Virginia Shooting Rep. Mo Brooks, R-Ala. meets with reporters in Alexandria, Va AP

Several of the roughly 25 Republicans on the field praised the quick response of the Capitol police, who were present as part of a security detail for Mr Scalise due to his position in the Republican leadership.

“Everybody probably would have died except for the fact that the Capitol Hill police were there,“ Kentucky Senator Paul Rand told MSNBC.

“Unfortunately [Mr Scalise] was hit and I hope he does well, but also by him being there it probably saved everyone else’s lives,” Mr Rand said. “Because if you don’t have a leadership person there, there would have been no security there.”

The shooter was quickly identified as James T Hodgkinson, from Illinois, who had owned a home inspection business.

The Belleville News-Democrat, the local newspaper, posted a photo of Mr Hodgkinson protesting outside a post office there in 2012, wearing sunglasses and a goatee and holding a homemade placard that read “TAX the Rich.”

Mr Hodgkinson was a member of many anti-Republican groups on Facebook including “The Road to Hell Is Paved With Republicans,” “Terminate The Republican Party,” and “Donald Trump is not my President,” a search of what appeared to be a profile page for showed.

Senator Rand Paul tells of hearing Alexandria shooting

“Trump is a Traitor. Trump Has Destroyed Our Democracy. It's Time to Destroy Trump & Co.” Mr Hodgkinson wrote in a post from March that linked to a Change.org petition calling for the removal of Trump from office.

His timeline was headed by a cover photograph of Bernie Sanders, the US senator from Vermont who campaigned unsuccessfully to be the Democratic Party’s presidential candidate last year.

Mr Sanders confirmed that Mr Hodgkinson had volunteered to work on his presidential campaign, but was quick to condemn the shooting.

“I am sickened by this despicable act. Let me be as clear as I can be. Violence of any kind is unacceptable in our society and I condemn this action in the strongest possible terms”, he said.

“Real change can only come about through nonviolent action, and anything else runs against our most deeply held American values,” he added.

US House Majority Whip Steve Scalise (Yuri Gripas/Reuters)

Representative Jeff Duncan of South Carolina said he had just left the practice and encountered the apparent gunman in the parking lot before the shooting. The man calmly asked which party's legislators were practising and Mr Duncan told him they were the Republicans. The man thanked him.

The FBI - which has taken over the investigation from local police - said it was too early to determine a motive in the shooting or whether the attack was an attempted political assassination. Meanwhile, the Bureau of Alcohol, Tobacco, Firearms and Explosives said it was running a trace on two weapons - a rifle and a handgun - recovered from the scene.

Dale Walsh, a friend of Mr Hodgkinson’s, told the Washington Post that Mr Hodgkinson was passionate about his beliefs but always appeared to be “in control.” He said he believes Mr Hodgkinson was “pretty well fed up” with the political situation, but he said the news of the shooting was a shock.

“I guess I just want to let people know that he’s not evil,” Mr Walsh said outside Mr Hodgkinson’s home. “I guess he was tired of some of the politics going on. Like in this state, we have politicians collecting a check and doing absolutely nothing for us.”

Referring to the morning's events, Alexandria Police Chief Michael Brown said at a press conference that officers received a call about an active shooter shortly after 7am and that they were on the location within three minutes.

One witness, Luther Murphy, told The Independent: “I was just walking through [by the baseball field] and I heard a bunch of gunshots And the police were shooting back.”

Mr Murphy added: “I left when I heard the gunshots.”

Another witness, Noah Nathan, said he was entering a dog park close to the field when the shooting occurred. “I'm pretty p***ed off,” he said. “I don't know if he had beef with the congressman or just wanted to have fun.”

Asked if it was a deliberate attack on Republican politicians, Mr Brooks told CNN: “People know who we are. It’s not a secret that we’re practising here… He was going after elected officials.”

Witness describes shootout between police and suspect at Alexandria shooting

Mr Scalise is in a stable condition at George Washington University Hospital, according to one congressional aide, where he is undergoing surgery.

Alex Heimberg, a student at the University of Virginia, had been at the YMCA’s gym with his friend Ryan Walsh, who goes to Virginia Tech, when the shooting occurred. Both are back in Alexandria for summer break.

Mr Heimberg told reporters he left the building, located about 50 to 75 yards from the baseball field, to purchase some deodorant at a nearby CVS at about 7am.

“I came back at around 7.05 and about five to 10 minutes later, there’s a shooting,” Mr Heimberg said. “We’re inside the basement and we heard these soft pops and thought that’s probably just stuff falling from upstairs.”

“A person comes down and says guys, there’s an active shooter, you need to get in the locker room,” he said. “This is one of the most innocent parts of the neighborhood - not someplace I'd expect this to occur,” Mr Heimberg said.

Mr Walsh said that people stayed in the locker room for about 20 minutes before starting to venture outside.

“We went upstairs to check out what was going on and there was bullet holes spread out across the front window of the [YMCA],” Mr Walsh said.