Everything we know about the attacks in London overnight.

Up to seven people are feared dead after a van veered off the road and mowed down pedestrians on London Bridge, turning a warm Saturday night into a scene of panic and chaos.

There are still no firm details of casualties, just that there are “multiple casualties” but the BBC reported that more than one person had been killed.

The Sun newspaper is reporting up to seven people are feared dead.

British Prime Minister Theresa May says it’s being treated as a terrorist attack.

Police said armed officers were also responding to reports of stabbings nearby. The BBC reported that more than one person had been killed.

The Metropolitan Police said they were called just after 10pm to reports of a vehicle hitting pedestrians on the bridge, which spans the River Thames in central London.

Soon after, there were reported stabbings at nearby Borough Market, a bustling area full of bars and restaurants.

The force said armed officers were sent to the scenes and shots were fired. They did not say if officers fired the shots.

Police also responded to another incident in the nearby Vauxhall area, but police later declared the incident was an unrelated stabbing.

The force tweeted a warning telling people in the area to run to safety, hide and then call police if it is safe to do so.

May said that “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.”

She said it was a fast-moving investigation and her thoughts were with “those who are caught up in these dreadful events.”

May’s office said she would chair a meeting of the government’s COBRA emergency committee on Sunday.

About two hours after the first reports of an incident, television images showed people walking away from the London Bridge area with their hands on their heads. Police tweeted that Londoners should “remain calm but be alert and vigilant”.

Nick Brandon of British Transport Police said the force had received reports of “multiple” casualties in an incident possibly involving a knife and a vehicle.

Multiple witnesses reported a vehicle veering off the road and hitting several pedestrians; others also said they saw a man with a knife.

Witnesses reported seeing injured people on the ground on the bridge. One, Holly Jones, told the BBC a white van veered off the road and struck as many as six people. She said she saw at least four or five people on the ground.

Another witness, Will Heaven, said he saw people who appeared to have been hit.

“We saw injured people on the road, injured people on the pavement,” he told Sky News.

He added that “it did not look like an accident”, saying it was clear that police “thought they were responding to something far more serious than a road traffic accident.”

A man who gave only his first name, Ben, told BBC radio that he “saw a man in red with a large blade, at a guess 10 inches long, stabbing a man, about three times” near Borough Market.

Transport for London said busy London Bridge station and two others were closed at the request of police.

The incident happened on a warm Saturday night in a busy area full of bars and restaurants.

It comes less than three months after an attacker ran down people with a vehicle on Westminster Bridge, killing four, then stabbed a policeman to death outside Parliament.

On May 22, a suicide bomber killed 22 people and injured dozens at an Ariana Grande concert in Manchester. After that attack, Britain’s official threat level from terrorism was raised to “critical,” meaning an attack may be imminent. Several days later it was lowered to “severe,” meaning an attack is highly likely.