LONDON — British police responded to eyewitness reports late Saturday that a van plowed into pedestrians on London Bridge. There were also reports of a stabbing incident in nearby Borough Market. It was not clear if they were related.

On London Bridge, witnesses described seeing a white van mounting the sidewalk and injuring at least six people at about 10:30 p.m. A BBC reporter who was on the bridge at the time said the van was driving around 50 miles per hour. Metropolitan police confirmed an incident but released few details.

British Transport Police said they have received reports of multiple casualties.

"We are dealing with an incident on #LondonBridge, when we have more information we will update this twitter feed," they tweeted.

London Bridge was closed in both directions, British Transport Police said. Twitter users began uploading footage of police on the scene.

In the incident at Borough Market, an area that houses many food stalls and pubs and is popular with tourists, Metropolitan police said armed officers had been sent to the area after reports of stabbings, possibly at a restaurant. Police said shots have been fired and urged people to flee the area.

Reports of the incident reflected fear that the incident could be terrorism. Britain has weathered two recent terrorism attacks in recent months. In March, four people were killed in London after Khalid Masood rammed his car into pedestrians on Westminster Bridge, before fatally stabbing a policeman outside the Houses of Parliament.

On May 22, a British-born suicide bomber killed 22 people and injured 59 others at Ariana Grande's concert in Manchester, England.