London alarm

A police officer sets up a cordon outside the Houses of Parliament in central London on Wednesday during an emergency incident in which a police officer was stabbed by an alleged assailant. There are also reports of as many as five people being “mowed down” on nearby Westminster Bridge ( inset). Transport for London said Westminster underground station has been shut at the police’s request

A police officer has been stabbed in the Houses of Parliament in central London on Wednesday, in what police are treating as a terrorist incident.

Commons Leader David Lidington told MPs the “alleged assailant was shot by armed police”.

There are also reports of as many as five people being “mowed down” on nearby Westminster Bridge, but police did not immediately confirm that report.

Amid confusing scenes, it appeared the incident may have unfolded in several locations, including on the busy Westminster bridge where tourists take pictures of Big Ben and other attractions.

A Downing Street source said Prime Minister Theresa May was “OK.”

Prime Minister Theresa May was seen being ushered into a silver Jaguar car as what sound- ed like gunfire rang out at Parliament during the incident.

Tom Peck, political editor for the Independent, tweeted: “There was a loud bang. Screams. Commotion. Then the sound of gunshots. Armed police everywhere.”

Press Association political editor Andrew Woodcock witnessed the scenes unfolding from his office window overlooking New Palace Yard.

“I heard shouts and screams from outside and looked out, and there was a group of maybe 40 or 50 people running round the corner from Bridge Street into Parliament Square.

“As the group arrived at the Carriage Gates, where policemen are posted at the security entrance, a man suddenly ran out of the crowd and into the yard.