British police said on Thursday a man had been arrested on Whitehall, the street home to numerous government ministries in central London, and a Reuters photographer saw at least two knives on the ground.

Police said no one had been injured in the incident close to Prime Minister Theresa May’s official Downing Street residence in Westminster but gave no further details. May was not at Downing Street at the time of the incident, her spokesman said.

The incident comes just over a month after a British-born convert to Islam ploughed a car into pedestrians on nearby Westminster Bridge killing four people before stabbing to death a police officer in the grounds of parliament.

Reuters pictures showed police officers standing by at least two knives lying on the ground.

Armed officers sealed off the area. A Reuters reporter and photographer saw police holding a dark-skinned, bearded man dressed in a hooded, black coat. His right hand appeared to have a bandage wrapped around it.