British police said Friday that they were "dealing with an incident at London Bridge," with some witnesses reporting hearing gunshots.
According to a tweet from the Metropolitan police, the incident is being treated as "though it is terror related" and that at least one man had been detained. The London Ambulance Service has declared a "major incident," the BBC reported.
Reports from the scene describe a group of men in a fight on the bridge. When police arrived, shots were heard, and the London Bridge station was closed, with no trains stopping there.
Prime Minister Boris Johnson issued a statement saying: "Iâm being kept updated on the incident at London Bridge and want to thank the police and all emergency services for their immediate response."
The BBC's Jim McManus told the news outlet that "Just a few minutes ago I was walking across London Bridge on the south bank to the north bank of the bridge. There appeared to be a fight going on on the other side of the bridge, with several men attacking one man. Police then quickly arrived, including armed police, and then a number of shots were fired at this man."
Police could be seen clearing the bridge, ushering people away from the area, which links the city's business district with the south bank of the River Thames.
London Bridge was the site of a previous attack in which several men ran people down on the bridge with a van,, before stabbing several other people in the nearby Borough Market.
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