LONDON - London police say they are treating a gun and knife incident at Britain's Parliament "as a terrorist incident until we know otherwise.''
The Metropolitan Police says in a statement that the incident is ongoing. It is urging people to stay away from the area.
Officials say a man with a knife attacked a police officer at Parliament and was shot by officers.
There are also reports of a vehicle hitting pedestrians on nearby Westminster Bridge.
The former Polish foreign minister, Radoslaw Sikorski, posted a video on Twitter that seems to show people lying injured in the road on Westminster Bridge.
Sikorski, a senior fellow at the Harvard Centre for European Studies, says he saw at least five people lying on the ground after being "mown down'' by a car.
Sikorski told the BBC he "heard what I thought what I thought was just a collision and then I looked through the window of the taxi and someone down, obviously in great distress.
"Then I saw a second person down, and I started filming, then I saw three more people down, one of them bleeding profusely.''
The leader of Britain's House of Commons says the Parliament complex is in lockdown.
A session of Parliament was suspended after the incidents.