LONDON: British Prime Minister Theresa May blamed `evil` extremist ideology on Sunday for an attack by knife-wielding men who mowed down and stabbed revellers in London, killing seven people, as police said they had arrested 12 suspects.

Saturday night`s rampage at the popular nightlife hub around London Bridge, by three men arriving in a van and wearing fake suicide vests, was the third deadly terrorist attack in Britain in three months and came only days before snap elections in the country.

National campaigning for Thursday`s general elections was suspended for the day out of respect for the victims, who included 48 people treated in hospital, some of them in life-threatening conditions.

No details were released about the suspected attackers who were shot dead within minutes by police.

The 12 arrests were made in the ethnically diverse east London suburb of Barking, with Sky News TVchannel reporting that a property raided by the police belonged to one of the killers.

Prime Minister May said the attack was driven by the same `evil ideology of Islamist extremism` behind last week`s Manchester suicide bombing that left 22 people dead, and the Westminster attack in March, which killed five.

`The recent attacks are not connected but we believe we are experiencing a new trend in the threat weface,` she said after chairing a meeting of the government`s emergency `Cobra committee`. She warned that perpetrators were inspired to attack `by copying one another`.

The assailants wore f ake suicide vests in a bid to increase the sense of panic as they lunged seemingly at random at the crowds gathered around London Bridge and Borough Market, which was full of restaurants and bars.

Holly Jones, a BBC reporter, saw a white van spee ding into crowds of people walking along the pavement on London Bridge, saying it hit five or six people.

Another witness said hesaw three men get out and thought they were going to help the victims.

Instead they `started kicking them, punching them and took out knives. It was a rampage really,` he said, adding that he heard a shout of: `This is for Allah`.

Canadian Prime Minister Justin Trudeau and French Foreign Minister Jean-Yves Le Drian announced that there had been one fatality each from their countries.

An Australian and four French nationals were among those hospitalised, their governments said, while a Spaniard was slightly wounded.

Eight officers fired an `unprecedented` 50 rounds at the three attackers, according to Metropolitan Police Assistant Commissioner Mark Rowley. The official said he was `increasingly confident that the attack was conducted by three individuals`. Britain was already on high alert following the attack on a concert on United States pop star Ariana Grande in Manchester, in which seven children were among the dead. Grande planned to take partin a benefit concert in Manchester on Sunday alongside stars including Pharrell Williams and Justin Bieber.

Some citizens were taking matters into their own hands, with a taxi driver showing an AFP reporter a spade that he now keeps in the car.

Terror response Ms May, who served as interior minister for six years before taking office after the vote last summer for quitting the European Union, said Britain`s response to the terrorist threat must change.

`We cannot and must not pretend that things can continue as they are,` she said.

She repeated calls for international action to combat extremist content online.

Ms May also warned that there was `far too much tolerance of extremism in our country`, promising to review counterterrorism efforts, including possibly increasing the jail terms handedoutincasesof terrorism.

The ruling Conservatives and the main opposition Labour party suspendednational campaign events for the day, although local campaigning continued.

`But violence can never be allowed to disrupt the democratic process, so those campaigns will resume in full tomorrow and the general election will go ahead as planned on Thursday, the prime minister said.

US President Donald Trump offered his help, highlighting his thwarted ban on travellers from six mainly Muslim countries.

Recalling the attack, Italian photographer Gabriele Sciotto, who was watching football at the Wheatsheaf pub in Borough Market, said he saw three men shot just outside.

In a picture he took, a man wearing combat trousers with a shaved head and what looked like a belt with canisters attached to it could be seen on the ground with two more bodies behind him.

`In two or five seconds, they shot all the three men down,` he said.-AFP