London Terror Attack: Shooting Outside UK Parliament Leaves 1 Killed, Dozen Injured

Also See| Attack Outside UK Parliament: In Pictures

Two people died in the incident, according to Sky News, but the total number of casualties was unclear.

Reuters reporters inside the parliament building heard loud bangs and shortly afterwards saw two people lying on the ground in a courtyard just outside, within the perimeter of the parliamentary estate.

His photographs showed people lying on the ground, some of them bleeding heavily and one apparently under a bus.

"I just saw a car go out of control, and just go into pedestrians on the bridge," a woman who gave her name as Bernadette told Sky News. She was on a tour bus on the bridge at the time.

"As we were going across the bridge, we saw people lying on the floor, they were obviously injured. I saw about 10 people maybe. And then the emergency services started to arrive. Everyone was just running everywhere.""HORRIBLE TO WATCH"

Some people suffered catastrophic injuries in the incident, British news agency the Press Association reported, citing a doctor at St Thomas's Hospital which is located directly across the River Thames from parliament.

Officials said an assailant had stabbed a policeman and then been shot.

Prime Minister Theresa May was safe after the incident, a spokesman for her office said. He declined to say where May was when the attack took place.Also Read: British PM Theresa May is Safe After Attack on Parliament: Spokesman

Journalist Quentin Letts of the Daily Mail newspaper told LBC radio that he had witnessed the stabbing of the policeman and the shooting of the assailant from his office in the parliament building.

"He (the assailant) ran in through the open gates ... He set about one of the policemen with what looked like a stick," Letts said.

"The policeman fell over on the ground and it was quite horrible to watch and then having done that, he disengaged and ran towards the House of Commons entrance used by MPs (members of parliament) and got about 20 yards or so when two plain-clothed guys with guns shot him."

Reuters reporters inside parliament saw a large number of armed police, some carrying shields, pouring into the building.

U.S. President Donald Trump told reporters at the White House he had been briefed on events in London but gave no details.

Britain is on its second-highest alert level of "severe" meaning an attack by militants is considered highly likely.

In May 2013, two British Islamists stabbed to death soldier Lee Rigby on a street in southeast London.