UK police shoot attacker during London Bridge stabbing incident

British police shot a man on Friday after a stabbing in the London Bridge area in the centre of the city, a security source told Reuters.

A video clip on Twitter filmed from a high vantage point showed what appeared to be three police officers backing away from a man lying on the pavement.

Two officers are pointing rifles at the man, who can be seen moving slightly. Reuters could not independently verify the footage.

?Police were called at 1:58 p.m. to a stabbing at (a) premises near to London Bridge,? police said in a statement. ?A man has been detained by police. We believe a number of people have been injured.?

It is believed that somebody was stabbed and police shot a suspect, the security source said.

London?s ambulance service said it had declared it a major incident and they had sent several crews to the scene.

Sky News said a man had been shot dead. Reuters was unable to confirm that report. Sky reported five casualties in the incident, citing police sources.

The bridge was locked down, with the Metropolitan Police saying they detained a man at a premises near to?London?Bridge. Armed officers closed off the famous landmark and evacuated passers-by.

Videos and photographs on Twitter showed several police cars and buses on the bridge and a truck straddling several lanes.

A BBC journalist reported that a number of gunshots had also been heard. Several men were seen restraining another, according to the BBC reporter.

The?London?Ambulance Service said it?s responding to the incident and has crews attending the scene, according to a post on its Twitter feed. Separately, Transport for?London?said it closed the bridge in both directions.

The U.K. is set to hold a general election on Dec. 12. The election campaign in 2017 was interrupted by terrorist attacks ? including one on?London?Bridge. In June 2017 three militants drove a van into pedestrians at the bridge, and then attacked people in the surrounding area, killing eight people.

British Prime Minister Boris Johnson said on Friday he was being kept updated on the incident.

?I?m being kept updated on the incident at London Bridge and want to thank the police and all emergency services for their immediate response.?

Britain?s opposition Labour leader Jeremy Corbyn said his thoughts were with those caught up in the ?shocking? incident.

?Shocking reports from London Bridge,? Corbyn said on Twitter. ?My thoughts are with those caught up in the incident. Thank you to the police and emergency services who are responding.?

Earlier this month, Britain lowered its national terrorism threat level to ?substantial? from ?severe,? its lowest level since 2014. (Courtesy Reuters and Bloomberg)