With elections looming, a string of terror attacks puts pressure on UK PM May

London police made a fresh round of arrests Monday after the country's third terror attack in less than three months as Prime Minister Theresa May came under mounting pressure over security three days ahead of elections.

The aftermath of Saturday night's rampage, which left seven dead and dozens wounded, dominated the campaign trail.

Labour leader Jeremy Corbyn said he would support calls for May to quit, as she had overseen a sharp reduction in police numbers in her past job as interior minister.

The attack, claimed by the ISIS group, saw three men wearing fake suicide vests use a white van to mow down people on London Bridge and then slash and stab revellers in Borough Market, a bustling late-night area.

Armed police reacted swiftly, killing the attackers within eight minutes with 50 shots.

Police said they carried out two early morning raids in east London on Monday and made "a number" of further arrests. Another 11 people were already in custody. 

Police named two of the three men behind the attack as Khuram Butt and Rachid Redouane, saying Butt was known to security services but there had been no evidence of "attack planning."

Butt was 27 and a British citizen born in Pakistan, while Redouane was 30 and "claimed to be Moroccan and Libyan", national counter-terrorism police chief Mark Rowley said in a statement.

The capital's police chief, Cressida Dick, said investigators had seized "a huge amount of forensic material" from the van.

"A very high priority for us is to try to understand whether they were working with anybody else," she told BBC television.

Dick and Mayor Sadiq Khan visited London Bridge on Monday as commuters returned to the scene of the attacks after some security cordons were removed.

No details have been released from the British authorities about the perpetrators. The Amaq news agency, which is affiliated with the IS group, said "the London attacks" were carried out by "a detachment of fighters from Islamic State."

A Canadian and a Frenchman were among the fatalities and citizens of several nations were among the 48 injured, including Australia, Bulgaria, France, Greece and New Zealand.

Eighteen are still in hospital in critical condition, according to an update by Britain's National Health Service.

French Foreign Minister Jean-Yves Le Drian was due to visit Britain on Monday to speak to the injured French nationals.

A vigil for the victims will take place at nearby Tower Bridge on Monday evening.

'Evil' ideology

May blamed "evil" Islamist ideology and vowed to crack down on extremist content online, warning that attackers were "copying one another".

She said the same ideology was behind the May 22 suicide bombing at a pop concert in Manchester that left 22 people dead, and the Westminster Bridge attack in March, which killed five.

Britain's response to the terror threat must change, she said. Thirty-four people have died and around 200 injured in the three attacks since March. 

"We cannot and must not pretend that things can continue as they are," she said, adding there was "far too much tolerance of extremism in our country".

But May's own record came under fire from the Labour Party, which — according to opinion polls questioned for their reliability — has closed the gap on her Conservatives ahead of Thursday's general election.

Campaigning resumed on Monday after being suspended for a day out of respect for the victims.

Labour leader Jeremy Corbyn noted that for six years, police numbers fell while May was in charge of security, implementing a budget-cutting drive under former premier David Cameron.

Asked by ITV television if he backed the calls for May to resign, he said: "Indeed I would."

"There's been calls made by a lot of very responsible people on this who are very worried that she was at the Home Office for all this time, presided over these cuts in police numbers and is now saying that we have a problem — yes, we do have a problem: we should never have cut the police numbers," he said.

His party is calling for a drive to hire thousands of officers for neighborhood duties, arguing that a grassroots approach will curb crime and radicalization.

May insisted that London police were happy with their resources, while counter-terrorism budgets had been protected and the number of armed officers had increased.

Britain was already on high alert following the attack at a concert by US pop star Ariana Grande in Manchester, northwest England, in which seven children were among the 22 dead.

Grande headlined a benefit concert in Manchester on Sunday, alongside stars including Pharrell Williams and Justin Bieber.

The national threat level was raised to maximum after the Manchester attack and troops were deployed at key public sites, but reduced to its second-highest level last weekend.

Saturday's rampage was the latest in a string of attacks to hit Europe, including in Paris, Berlin and Saint Petersburg.

Global leaders sent messages of support, though US President Donald Trump raised British hackles by attacking Khan on Twitter.

On Sunday, Trump misconstrued remarks the mayor had said in which he told Londoners that there was "no reason to be alarmed" by an increased police presence in the coming days.

In a notable contrast to Trump's attack, the acting US ambassador in London, Lewis Lukens, commended Khan for his "strong leadership".