The police have released a statement after a suspected terrorist attack took place in Westminster.

A police officer has been stabbed and an alleged attacker shot outside the Houses of Parliament, shortly after a vehicle is reported to have mowed into members of the public on Westminster Bridge.

Two people have been confirmed dead and a number of others, including a police officer, have been injured, according to a junior doctor at St Thomas' Hospital. Some victims have been described as having "catastrophic'' injuries.

Police are treating the London shooting which took place on Wednesday afternoon as a terrorist incident until further notice but details of the attack remain unclear.

Staff inside parliament found themselves prohibited from leaving the building after at least three gun shots were heard by those inside Westminster and ambulances and other emergency vehicles dominated scenes.

In a statement given at New Scotland Yard, Commander BJ Harrington said the police had received a number of differing reports, including a person spotted in the river, a car in collision with pedestrians and a man armed with a knife.

The Commander said there had been a number of causalities, including police officers, but they were unable to confirm numbers or the nature of these injuries at this stage. He said a full counter-terrorism investigation is already underway.

Here is Commander Harrington's statement in full:

"Since 2.40pm this afternoon the Metropolitan Police Service has responded to an incident in the area of Parliament Square, and the Senior National Coordinator has declared this a terrorist incident.

"And although we remain open minded to the motive, a full counter-terrorism investigation is already underway - this is led by the Met's Counter Terrorism Command.

In pictures: Westminster attack Show all 9 1 /9 In pictures: Westminster attack In pictures: Westminster attack An air ambulance lands after gunfire sounds were heard close to the Palace of Westminster in London PA wire In pictures: Westminster attack MPs wait until the situation is under control in Westminster. 'The alleged assailant was shot by armed police,' David Lidington, leader of the House of Commons, told the house. BBC News In pictures: Westminster attack Crowds gather in Westminster after shooting incident, which police are treating as terror attack BBC News In pictures: Westminster attack Police were also called to an incident on Westminster Bridge nearby AP In pictures: Westminster attack Early reports indicate the car, which mounted the pavement on Westminster Bridge and mowed into around a dozen people, was the same vehicle which then rammed into the railings of the Palace of Westminster, just around the corner Reuters In pictures: Westminster attack Security sources described the suspected assailant as a middle-aged Asian man, who is understood to have left the car before attacking a police officer with a seven-to-eight inch knife PA wire In pictures: Westminster attack Police have asked people to avoid the immediate area to allow emergency services to deal with the ongoing incident AP In pictures: Westminster attack One woman has died and a number of others, including the police officer, have been hurt, according to a junior doctor at St Thomas' Hospital Reuters In pictures: Westminster attack At least three gun shots were heard by those inside Westminster, and proceedings in the House of Commons have been suspended AP

"At this stage I will confirm what we know has happened, but I will not speculate.

"We received a number of different reports - which included a person in the river, a car in collision with pedestrians and a man armed with a knife.

"Officers were already in the location as part of our routine policing operation. Immediately, additional officers were sent to the scene and that included firearms officers.

"We are working closely with the London Ambulance Service and the London Fire Brigade.

"I'd like to repeat our request for the public to avoid the following areas: Parliament Square; Whitehall; Westminster Bridge; Lambeth Bridge; Victoria Street up to the junction with Broadway and the Victoria Embankment up to Embankment tube. This is to allow emergency services to deal with this ongoing incident.

"There is an ongoing investigation being led by the Counter Terrorism Command and we would ask anybody who has images or film of the incident to pass those to police.

"We know that there are a number of causalities, including police officers, but at this stage we cannot confirm numbers or the nature of these injuries.

"Our response will be ongoing for some time as it is important that we gather all possible information and evidence. Public safety is our top priority and we are reviewing our policing stance across London and throughout the course of this afternoon there will be additional police and officers deployed across the Capital.