At least 20 people were injured and four reported dead in London on Wednesday after a car crashed into pedestrians near the British parliament and an assailant stabbed a policeman in what police called a terrorist incident.
The knifeman was then shot by police in the shadow of Big Ben, where he had tried to force his way into a courtyard just outside the Houses of Parliament.
The incident appeared to have unfolded in several locations, including on nearby Westminster Bridge where eyewitnesses said a car had crashed into pedestrians.
Reuters reporters inside parliament heard loud bangs and shortly afterwards