Report of multiple casualties in incident on London Bridge

Will Heaven, the managing editor of The Spectator magazine, said on Twitter he saw "two casualties - one on pavement, one edge of road" and reported seeing armed police on the bridge.

Earlier, Trump retweeted the Drudge Report when it referred to "fears of a new terror attack", although the nature of the incidents had not yet been confirmed by authorities.

Witnesses described a van speeding into pedestrians on London Bridge and then a knife-wielding man sprinting towards a bar packed with revellers enjoying a Saturday night out.

Footage emerged of hundreds of Londoners leaving the scene at London Bridge, where tens of thousands gather on weekends to visit clubs, bars and restaurants.

The force initially said they were also responding to a reported third incident, in the Vauxhall area of London.

British Prime Minister Theresa May says the incidents involving a vehicle and reported stabbings in London "is being treated as a potential act of terrorism". The drivers of the van then ran out with knives, attacking people on the street and in businesses in nearby Borough Market.

Mrs May offered her "huge gratitude" to the emergency services attending the incidents.

"This is a fast-moving investigation. Police told us to get out and then there was more gunfire".

Labour leader Jeremy Corbyn called the news "brutal and shocking" in a tweet.

"Our hearts are with the families and loved ones of the victims. Thank you to the emergency services".

Met urged people to remain calm, but also asked them to be alert and vigilant.

"Whatever the United States can do to help out in London and the U.K., we will be there", he tweeted. A BBC reporter who was on the bridge at the time said the van was driving around 50 miles per hour. The witness said the van hit five to six people. Then a few yards on, I saw another pson lying down and a woman screaming, then a couple of bodies on the right lane, then more people on the left lane. It said the blasts were believed to be controlled explosions carried out by police. "They all have paramedics assisting them at the moment".

"Now the area is completely closed with police cars going one way and ambulances going the other", he told Reuters.

On March 22, a knife-wielding man mowed down pedestrians on London's Westminster Bridge before fatally stabbing an armed police officer to death just inside the gates of Parliament. He said he did not know the seriousness of the injuries.

"I'd say there are about four severely injured people. So the police checking the Thames", Ms Jones said. He said he threw chairs, glasses and bottles at the attackers in a bid to stop them.

The police were urging the public to run to a place of safety, or hide if they can not.

Witnesses said they saw a white van struck pedestrians on London Bridge. He said he ran and hid, and was then told by police to run home.

"He looked in a bad way".

Mark Roberts, a witness, told CNN that he was on the bridge when the white delivery van came barreling down the road.

  • Tracy Klein