Seven people have been killed in a terror attack at London Bridge and Borough Market.

A speeding van ploughed into pedestrians on London Bridge before three attackers jumped out and began stabbing people.

The Met Police tweeted: "At 0025hrs 4/6/17 the incidents at #LondonBridge & #BoroughMarket were declared as terrorist incidents."

A total of 48 people were injured in the attack, and three suspects were shot dead by police.

Emergency services were seen treating people lying injured at the junction of Thrale Street and Southwark Street, near Borough Market.

One woman was taken away on a stretcher while others sat injured on the ground, with shocked people crying and shouting around them.

Frightened people were led up Southwark Street away from Southwark Bridge Road, and police officers were seen screaming to people and ordering them to run.

A couple of hours after the initial incidents, what are thought to have been controlled explosions were heard on London Bridge and near Borough Market, while a photo on social media appeared to show a man on the ground with canisters strapped to his body.

A stabbing at Vauxhall was unrelated, the force added.

Prime Minister Theresa May said she was being updated by officials on the "fast-moving" situation, adding: "I can confirm that the terrible incident in London is being treated as a potential act of terrorism."

She will chair a meeting of the Government's Cobra emergency committee on Sunday, No 10 said.

Witnesses have described seeing a speeding vehicle veer into crowds on London Bridge just after 10pm and people being stabbed in Borough Market.

A van reportedly swerved off the road on London Bridge and, in the food market, witnesses said they saw a man with a large blade.

Witness Eric was on the south side of London Bridge when he saw the van on the wrong side of the road. 

He told BBC Radio 5Live: "It veered to the right and people were trying to run away from it."

When it stopped, he said three people got out and he thought they were going to help the people who had been hit.

"But the three people literally started kicking them, punching them, and took out knives. It was a rampage really," he said.

The three men ran off towards the nearby bars and restaurants and there was a shout of "this is for Allah", he added.

Husband and wife Ben and Natalie told BBC Radio 5 Live they were outside Borough Market, coming up the entrance of the underground when they saw the incident.

Ben said: "We saw people running away and then I saw a man in red with a large blade, at a guess 10 inches long, stabbing a man, about three times.

"It looked like the man had been trying to intervene, but there wasn't much he could do. He was being stabbed quite coldly and he slumped to the ground."

Ben said the man walked away boldly with another person, and went towards the Southwark Tavern. He said they saw a metal chair being thrown towards the man.

"Then we heard three gunshots, definitely gunshots, and we ran."

Jamie, a witness who was in a restaurant on Rochester Walk near London Bridge, told the Press Association: "We were in the Black and Blue restaurant, we heard a fight and everyone got up and everyone rushed out of the restaurant and we heard a massive, massive bang.

"Then we hid under the table and people came into the restaurant and knocked a bunch of stuff over, like the till.

"And then we ran into the restaurant into the kitchen, where there was a bunch of other people and a guy had been stabbed and he was cut and he was bleeding quite a lot."

He added that they waited in the kitchen for "quite a while" before they were evacuated.

A female companion said: "We were in the restaurant and we just saw three guys come into the restaurant, stabbed someone in the face and someone in the stomach.

"One of them had a big knife, then he came in and walked around the restaurant, I guess they just kind of stabbed anyone that they saw and knocked things on the ground and then we just hid."

Alex Shellum was in The Mudlark pub, close to London Bridge, at around 10pm when a woman in her early 20s "staggered into the pub".

"She was bleeding heavily from the neck and from her mouth," he told BBC News.

"It appeared to myself and to my friends that her throat had been cut. People went to her aid."

He said the pub was then closed and armed police told them to leave the area.

He said: "I could see on my left a further individual was having CPR performed on them by the emergency services."