Six people have been killed and at least 48 injured in a terror incident in London in which three male attackers were shot dead by police.
A white van hit pedestrians on London Bridge at about 22:00 BST on Saturday, then three men got out and stabbed people in nearby Borough Market.
Police said the three men were wearing fake bomb vests.
One of those hurt is a police officer who was stabbed after going to help. His injuries are not life-threatening.
The Conservatives, Labour and the SNP have suspended national general election campaigning and the prime minister is chairing a meeting of the government's Cobra emergency committee.
Theresa May described Saturday night's events as "dreadful", while Labour leader Jeremy Corbyn called them "brutal and shocking".
London Mayor Sadiq Khan said it was "a deliberate and cowardly attack on innocent Londoners", but the capital remained the "safest global city" and Londoners would not be cowed by terrorism.
It is the third terror attack in the UK in three months following the car and knife attack in Westminster in March, which left five people dead, and the Manchester bombing less than two weeks ago, in which 22 people were killed.
Metropolitan Police Assistant Commissioner Mark Rowley said it was believed there were only three attackers involved and the explosive vests they were wearing were "hoaxes".
One social media user posted a photograph appearing to show an attacker lying on the ground outside a pub in the food market, with the fake vest visible.
Among the main developments:
- More than 80 medics were sent to the scene. The injured, some of them critical, are being treated in five London hospitals
- The Met Police has set up a casualty bureau on 0800 096 1233 and 020 7158 0197 for people concerned about friends or relatives
- Two Australian citizens "have been directly impacted," says the country's Prime Minister Malcolm Turnbull
- At least two French citizens have been injured, according to the French president's office, quoted by Reuters
BBC reporter Holly Jones, who was on the bridge at the time of the attack, said the van was "probably travelling at about 50 miles an hour".
"He swerved right round me and then hit about five or six people. He hit about two people in front of me and then three behind," Ms Jones told the BBC News channel.
Another eyewitness, Robbie, was sitting in a taxi opposite the Barrowboy and Banker pub on London Bridge.
"I saw about 20 or 30 people rushing to get back into the pub and five seconds later a big white van came screeching down the pavement," he told BBC Radio 5 live.
"Two or three people jumped out. Initially, I thought it was a road traffic incident and the people had jumped out to see if anyone was injured, but I could tell immediately, they looked very aggressive."
His friend Josh came out of the pub a few seconds later and saw people running up to the bridge from Borough Market.
"A chap ran up and I heard him shout, 'He's got a knife, he's stabbing people.'"
Another witness, Gerard, told the BBC: "They were running up shouting, 'This is for Allah.' They stabbed this girl maybe 10 times, 15 times. She was going, 'Help me, help me.'"
Gerard said he chased the attackers, who were running into pubs and bars, and threw bottles, chairs and other items to try to stop them.
Steven Gibbs, who was drinking in St Christopher's Inn, just metres from the scene, told the BBC: "A black cab drove past and the driver shouted, 'Terrorist attack, run!'
"I stood up to take a look and then all of a sudden there were gunshots. Lots of people were screaming."
Steven was taken into the basement of the bar before the police came in and told everyone inside to run.
"I've never been so scared in my life," he said,
Reproduced under licence from BBC News © 2017 BBC