British police rushed to an incident on London Bridge on Saturday after witnesses said a van ploughed into pedestrians and another witness told Reuters she saw people with throats cut on London Bridge.
Police said they were dealing with an incident but gave no further details while the London Ambulance Service said it was sending multiple resources to the incident. A Reuters reporter near the scene said she saw 10 police cars rushing towards London Bridge.
One witness told Reuters that she saw what appeared to be three people with knife wounds and possibly their throats cut.
A witness told the BBC she saw a speeding white van veering into pedestrians. The witness said the van hit five to six people. Reuters television pictures showed dozens of emergency vehicles in the area around London Bridge.
One witness named Tony Murphy talked to Sky News saying that he heard "significant gunfire" near the area.
London's transport authority said London Bridge rail station had been closed at the request of the police.
On May 22, a suicide bomber killed 22 people at a pop concert by U.S. singer Ariana Grande in Manchester in northern England.
The Manchester bombing was the deadliest attack in Britain since July 2005, when four British Muslim suicide bombers killed 52 people in coordinated attacks on London's transport network.
This is a developing story.