Tory MP Tobias Ellwood attempted to save the life of a policeman attacked in the grounds of the Palace of Westminster, who later died.

The foreign minister – a retired soldier - reportedly attempted to perform mouth-to-mouth on the officer.

Photos of the chaotic scene appeared to show Mr Ellwood leaning over the victim with his two arms extended as paramedics and police crowded around.

Westminster terror attack: Timeline of events

He remained with the victim while an air ambulance landed on nearby Parliament Square.

A source told The Telegraph: “[He] tried to give mouth-to-mouth and stem blood flow from multiple stab wounds to the officer until the chopper and medics arrived.”

Police confirmed there were a number of casualties in the Westminster attack, including police officers.

Commander BJ Harrington said: "We know there are a number of casualties including police officers but at this stage we cannot confirm numbers or the nature of these injuries.

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

"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."

At least 10 patients have been treated on Westminster Bridge and a number of hospitals are on alert, London Ambulance Service said.