One person’s died after a van was driven into crowds outside a Muslim centre in north London.
Eight people have been taken to hospital from the scene at Finsbury Park.
The 48 year-old driver of the van was held by members of the public and has been arrested by police.
British Prime Minister Theresa May who will chair an emergency meeting later said police were treating it “as a potential terrorist attack”.
She described it as a “terrible incident”, adding her thoughts are with those who have been injured, their loved ones and the emergency services on the scene.”
London’s mayor has described the Finsbury Park incident as a horrific terrorist attack.
In a statement on twitter Sadiq Khan says it appears to be an attack on a particular community.