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 and SNP have suspended national general election campaigning and the prime minister will chair a meeting of the government's Cobra emergency committee later.
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.
- More than 80 medics were sent to the scene. The injured, some of them critical, are being treated in five London hospitals
- 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.
Gunshots were heard in the area while one social media user posted a photograph appearing to show one of the attackers lying on the ground outside a pub in the food market, with what police now say was a fake bomb vest strapped to his body.
A bomb disposal team was later called to Borough Market and local residents told to leave their homes.
No-one has been able to clean up the empty pint glasses on the tables outside Belushi's bar on Borough High Street - a stark reminder of what happened in London Bridge last night.
It's 8am and dozens of police cars and cordons remain in the area, blocking anyone from walking up to Borough Market, where the tragedy unfolded.
Dozens of people wait by the police cut-off areas in a confused state trying to work out how to get home or to work.
But no-one is prepared to give up.
There is a determined resilience in the air with nurses and railway workers walking miles out of their way to try to get to their jobs.
Security officer Mohammed Osman, who works on Borough High Street, had to wait for an hour before he was allowed through to his place of work.
He said: "I'm not feeling worried. I'm strong enough. These enemies are trying to divide us but we have to be together."
Eyewitness Will Orton, who was also in a pub close to the scene, said: "The bouncers did a really good job, they shut the doors and locked everyone in.
"There was panic - it seemed like it was literally outside the door."
Vilwar Hussein helped carry the injured police officer to nearby Guy's hospital and recalled seeing a wound in his chest "and blood everywhere".
Earlier, Vilwar said he saw the white van perform a U-turn on London Bridge before driving back southwards along the pavement.
People running down Borough High Street on the south side of London Bridge
Armed police were sent to the area
Counter-terrorism specialist firearm officers were later in attendance
Ambulances attended to the injured on London Bridge
Transport for London (TfL) said London Bridge had been closed in both directions, with neighbouring Southwark Bridge also shut.
TfL said there were further closures in Borough High Street, while on the north side of the river, road closures included Lower Thames Street.
Facebook has activated its safety check so people in London could post a message to let friends and relatives know they were safe.
Police led people to safety after the attack
Police and ambulance could be seen on the south side of London Bridge
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