A police officer has been stabbed in the Houses of Parliament in central London, 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.
MPs said they had heard three or four gunshots. 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 sounded like gunfire rang out at Parliament during the incident.
Staff inside Parliament were told to stay inside their offices.
Tom Peck, political editor for the Independent, tweeted: “There was a loud bang. Screams. Commotion. Then the sound of gunshots. Armed police everywhere.”