One Australian is in hospital in London following the terror attacks, Prime Minister Malcolm Turnbull has just announced.
Another Australian is also affected, but inquiries are ongoing about their condition, Mr Turnbull said.
"This attack is yet another cruel example of the new reality in which we live, the ever-present threat of murderous Islamist terrorists, intent to harm our communities, our way of life and the freedoms we hold dear," Mr Turnbull told a press conference.
He didn't mince his words.
"We will never, ever bow to terrorism.
“We will continue, as will the people of Britain, to lead our lives the way we always have. We defy the terrorists. In the field, we find them, we destroy them, we kill them.
“At home our agencies disrupt their plots, uncover their networks, bring them to meet their just desserts in the courts and lock them up where they can no longer do us harm.”
It's almost 7am on Sunday in Britain and the country is waking up to the third terrorist attack in as many months. That's if anyone got any sleep.
Here are some of the front pages from newspapers around the country on Sunday morning:
Authorities have just announced that 48 people were admitted to hospital after the attacks.
A number of others were treated at the scene for minor injuries.
More than 80 ambulance medics responded to the incident.
There has been no change to the UK terror threat level, which remains at 'severe'.
Following the Manchester Arena attack two weeks ago, the level was raised to 'critical' - the highest level on the scale - which means an attack is "expected imminently".
But on May 27 it was subsequently downgraded back to 'severe', which means an attack is "highly likely".
It was a beautifully mild evening in London when visiting Australian Senator Sam Dastyari headed out to the Arabica restaurant in the city's popular Borough Market for a quiet dinner with friends from the UK Labour party.
It was to be their last real chance to relax before the final build up to Britain's general election on Thursday
The group were not far into their meal when the screaming started, and a young woman covered in blood rushed past where they were sitting.
"Your first thought is obviously there has been a bar incident, maybe a fight or something" Senator Dastyari told Fairfax Media.
Police have not revealed the identity of the suspects.
All we know so far is that three people have been shot dead by police after going on a stabbing rampage through Borough Market.
We don't know who these three people were.
Six people were killed and more than 30 injured when a van driving at high speed mowed down pedestrians on London Bridge, before the occupants got out and began stabbing patrons at nearby bars and restaurants, in what police have declared as a terrorist attack.
Police said the three attackers, who were wearing what appeared to be explosive vests, were then shot dead in a confrontation with police outside the popular Borough Market, which was packed with people on Saturday night.
Metropolitan Police Assistant Commissioner Mark Rowley said police officers shot dead the suspects within eight minutes of receiving the first emergency call.
The vests the men were wearing were later determined to be fake, he said.
The British Prime Minister has returned from her local electorate to Number 10 Downing Street. She will chair a crisis meeting of cabinet ministers and heads of intelligence agencies early in the morning, local time.
Such briefings are known as COBRA meetings, as they are commonly held in Room A of the Cabinet Office Briefing Rooms.
1.50pm: Dashcam footage of the van has emerged.
1.30pm: London Ambulance have taken 30 patients to five hospitals across London.
A Scotland Yard spokesman said six people had been killed in the terrorist attacks on London Bridge and Borough Market.
The car that struck pedestrians on London Bridge drove on to Borough Market. "The suspects left the vehicle, attempting to stab a number of people," Metropolitan Police Assistant Commissioner Mark Rowley said.
This included a transport police officer, who was treated for non-life threatening injuries.
Eight minutes after receiving the first reports of the bridge attack, police had shot dead three armed attackers. The attackers appeared to be wearing explosives but that was part of a hoax, Mr Rowley said.
"Our current belief is that there were three attackers, but this is early on."
This is the sixth terror attack in Europe this year, and the third in the UK.
Manchester, May 22: A suspected suicide bomber kills 22 people, including children, and injures 59 following an Ariana Grande pop concert in Manchester.
Stockholm, April 7: A hijacked truck ploughs into a busy pedestrian area in central Stockholm, killing five people. A 39-year-old Uzbek man is charged over the attack.
London, March 22: A man drives his car into pedestrians on Westminster Bridge in central London and stabs a policeman to death outside parliament. Four pedestrians die of their injuries and the attacker is shot dead.
Paris, February/March: Soldiers manage to stop an attempted attack at Paris Orly airport by shooting a man who tries to take a patrolling soldier's gun. In early February, a soldier on patrol shoots an Egyptian assailant wielding a machete.
Istanbul, January 1: A mass shooting occurred at a nightclub in the Besiktas district of Istanbul on New Year's Day. The attack occurred at the Reina nightclub in Ortakoy, where hundreds of people were celebrating the New Year. Islamic State claim responsibility for the attack.
Leaders such as Canadian Prime Minister Justin Trudeau and French President Emmanuel Macron have expressed their nations' solidarity with Britain on social media.
So, too, have Australian Prime Minister Malcolm Turnbull and Opposition Leader Bill Shorten.
At least two people are dead and police still searching for the attacker, according to British media.
The BBC said it had confirmed more than one person has been killed.
Sky News has reported that police are still searching for an armed gunman.
A heavy police presence remains in central London
London police have opened a casualty bureau for people to call in search of missing friends and family. Armed officers continue to stand guard around London Bridge and Borough Market.
London Bridge is set to remain closed all night.
It is now 3.34am in England.
Our prayers and resolute solidarity are today as always with the people of Britain in the face of the shocking terrorist attacks in London.— Malcolm Turnbull (@TurnbullMalcolm) June 4, 2017
Emergency services have treated the wounded on scene.
At least 20 people have been injured.
The first paramedics arrived six minutes after reports of the London Bridge attack, the London ambulance service said.
The Metropolitan Police have just released a summary of what we know about the attacks.
It said police first responded to reports of a vehicle colliding with pedestrians on London Bridge at 10.08pm local time.
"Officers have then responded to reports of stabbings in Borough Market," police said. "Armed officers responded and shots have been fired."
At 12.25am, the attacks were declared terrorist incidents.
There is no official death toll yet. The BBC said it was told by a police officer at least one person had died. More than 20 are expected to have been injured.
There is no confirmation of reports that attackers have been shot dead by police.
People near London Bridge and Borough Market have been told to run away or hide.
Explosions heard near the scenes are believed to be controlled police blasts, local media report.
Three major London hospitals said on Sunday that they were on lockdown after attacks near London Bridge late on Saturday in which up to seven people are feared dead.
"Due to the ongoing incident in central London, Guy's, St Thomas' & @EvelinaLondon are on lockdown to keep patients, relatives and staff safe," the authority that runs the hospitals said on Twitter.
Guy's Hospital is next to London Bridge rail station and St Thomas' Hospital and the Evelina children's hospital are located a mile away.
One worker at a Borough Market restaurant described in faltering English how the attackers came inside.
"People crazy, they just with the knife, they push the people, they kill it, like they don't care," he said.
The worker said he saw three people attacked but heard there were more.
From the BBC's live reporting:
Alex Shellum was in the Mudlark pub with his girlfriend and two friends, underneath London Bridge, at the time of the incident.
"At around 22:00 BST an injured woman came into the pub seeking assistance.
"She was bleeding heavily from the neck - it appeared that her throat had been cut. People sought to stem the bleeding and the pub was closed.
The BBC has reported several eyewitness accounts of stabbings near Borough Market.
A security guard, who did not wish to be named, said he saw four people stabbed by three attackers.
Another man, called Ben, said: "I saw a man in red with quite a large blade, I don't know the measurement I guess maybe 10 inches. He was stabbing a man...he stabbed him about three times fairly calmly."
In a statement, British Prime Minister Theresa May said:
"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.
"This is a fast-moving investigation. I want to express my huge gratitude to the police and emergency services who are on the scene. Our thoughts are with those who are caught up in these dreadful events.
Foreign Minister Julie Bishop says she has spoken with Australia's High Commissioner, Alexander Downer, about the incident.
"He has activated our consular support. He has made contact with all our employees and their families at the High Comission and so far we have had no reports of any Australians involved," she told Sky News.
"We have seen this pattern before, including in the Westminster Bridge attack earlier this year.
"I was in New York a couple of weeks ago when a similar incident - occurred where a car ploughed into pedestrians in Times Square - but it ended up being a case of drugs and alcohol, it wasn't a terrorist incident."
British police have declared a "major incident" after multiple people were reported to have been injured when a van veered into pedestrians on London Bridge.
Witnesses reported that a white van was travelling fast - about 80km/h - when it mounted the sidewalk and ploughed into a group of people crossing the Thames River on foot.
Holly Jones, a BBC reporter who was on the bridge at the time, said five people were being treated for injuries.
Police later confirmed a second incident at Borough Market, which is near the bridge.
Police said that armed officers were responding to the scene.
Witnesses reported hearing gunshots at the bridge around 10.30pm, local time.
"I heard many gunshots and I heard people running away," said Joe Dillon, 23, who was near London Bridge when the incident occurred.
"Police officers were shouting: 'Get out of here, you need to go!' I heard at least eight rounds of gunshots, but I'm not sure who was shooting. When I arrived a second after I had heard the screams and the shots, I saw five or six officers running toward the van."
Police closed the bridge and urged the public to avoid the area.
Diners at restaurants near the bridge said they were told by police to run.
The incident comes less than two weeks after 22 people were killed in a bomb blast following a Manchester concert.
And it comes three months after a driver killed four pedestrians on another Thames crossing, Westminster Bridge.
That assailant then stabbed to death a London police officer at the gates of Parliament.
The BBC has reported one of its journalists, Holly Jones, was on the bridge at the time and said the van was "probably travelling at about 50 miles an hour".
Jones estimated about five people were injured after the van mounted the kerb.
The managing editor of the Spectator magazine, Will Heaven, tweeted that he was on the bridge and saw "injured pedestrians, first responders, armed police, people running north".
A witness told Reuters she had seen what appeared to be three people with knife wounds.
Another witness told Sky News he heard bursts of gunfire but other witnesses did not recall hearing shots.
London Transport says London Bridge station has been closed at the request of police due to a "major police incident".
Metropolitan Police tweeted armed police were responding to incidents on the bridge and at Borough Market.
The mayor of London, Sadiq Khan, advised people to follow the police Twitter account for updates as emergency services dealt with the incident.
Labor senator Sam Dastyari said on social media he was having dinner near the bridge and was evacuated past the scene by police after they placed the restaurant in lockdown.
Fairfax Media correspondent Latika Bourke said she saw dozens of people being evacuated from the area.
- Fairfax Media, Washington Post
The story, London Bridge closed as van ploughs into pedestrians, first appeared on the Sydney Morning Herald.