Here is what we know about the attack, which came 12 days after a suicide bombing in Manchester.
The attackers were shot dead by the police at the scene.
Here is what we know about the attack, which came 12 days after a suicide bombing in Manchester and just days ahead of Britain's general election on Thursday.
Police received reports of a van speeding into pedestrians on London Bridge at 10:08pm (2108 GMT).
These emergency calls were quickly followed by reports of multiple stabbings in the popular Borough Market area on the south side of the bridge.
After the white van crashed into fencing by Southwark Cathedral, knife-wielding men sprinted towards nearby bars packed with revellers enjoying a night out.
Armed police were quickly on the scene and three assailants were shot and killed within eight minutes of the first call to emergency services.
They were wearing what appeared to be explosive vests that were later discovered to be fake.
Eight armed police were dispatched to the site, firing about 50 rounds -- "an unprecedented number," according to a Metropolitan Police statement on Sunday. A member of the public also received non-critical gunshot wounds.
Seven people were killed and 48 others were initially admitted to hospital. Of these, 36 are still being treated, 21 of whom are in a critical condition.
The injured included a London transport police officer who was one of the first responders on the scene. He was stabbed in the face and leg.
An off-duty police officer was also injured.
A Canadian national and a Frenchman were among those killed, while seven other French nationals were wounded and another remains unaccounted for.
A Spanish citizen and one Australian were also injured.
Police on Monday carried out fresh raids and arrested "a number of people" in East London after detaining 12 people a day earlier in the suburb of Barking.
Seven women and four men, aged 19 to 60, were in custody on Sunday, with one 55-year-old man later released without charge, police said.
The white Renault van used in the attack was recently hired by one of the attackers, the police added.
London police said more officers -- armed and unarmed -- would be deployed across the city, and there would be additional security measures on London's bridges.
A similar attack in March on Westminster bridge, carried out by 52-year-old Briton Khaled Masood, killed five people and injured more than 50.
London's Metropolitan Police said they will release the identities of the attackers "as soon as operationally possible".
Prime Minister Theresa May said the attackers were driven by "Islamist extremism".
The Islamic State group claimed responsibility for Saturday's rampage.
IS previously said it carried out both the Westminster attack and suicide bombing at a pop concert in Manchester on May 22, which left 22 people dead.
London Bridge is one of the main arteries leading into the heart of the City business district in the British capital.
Borough Market, at the south end of the bridge, is a world-famous food hall and a trendy nightlife area always packed with revellers on a Saturday night.
The Shard skyscraper -- Britain's tallest building and one of the best-known sights on the London skyline -- is also at the south end of London Bridge.
The scene of the attack is also right next to London Bridge station, a key railway terminus and a busy interchange on the London Underground network. Police have cordoned off the area to carry out their investigation, which is having a big impact on transport.