Theresa May confirms London attacks "potential acts of terrorism".

London Metropolitan Police have confirmed a third incident in Vauxhall believed to be connected to two “potential acts of terrorism” on London Bridge and the Borough Market is an unrelated stabbing.

The announcement comes a mere hours after police shut down London Bridge amid reports a white van plowed into more than 20 civilians at about 10pm local time. Within minutes police then responded to a coordinated incident at the Borough Market.

British Prime Minister Theresa May says the incidents in London are being treated as potential acts of terrorism.

“Following updates from police and security officials, I can confirm that the terrible incident in London is being treated as a potential act of terrorism,” May said just over four days before voting is due to begin in a June 8 national election.

“This is a fast moving investigation,” May said.

“I want to express my huge gratitude to the police and emergency services who are on the scene. Our thoughts are with those who are caught up in these dreadful events.”

Britain’s official terror threat had recently been lowered from “critical” after a bombing killed 22 people at an Ariana Grande concert in Manchester last month.

With AAP.