Police have carried out further raids in east London in connection with Saturday night's terror attack at London Bridge and Borough Market.
Metropolitan Police officials confirmed "a number" of arrests were made in the Dagenham and Newham areas in the early hours of Monday.
Locals reported hearing "loud flash bangs and gunshots" around 4.15am, The Independent reports.
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A photo uploaded to Twitter by Sky News correspondent Mark White shows police standing guard outside a car servicing business, believed to be one of the properties involved, on Ripple Road in Dagenham.
It follows the arrest of seven women and five men in Barking, east London, yesterday in connection with Saturday night's attack in London. A 55-year-old man, was later released without charge.
Detectives are trying to establish whether the three attackers were part of a wider terror network. Islamic State called them its "soldiers", although several analysts have expressed scepticism as to whether they had any concrete link to the group.
Writing in The Guardian, Jason Burke, the author of several books on Islamist terrorism, says IS "has started claiming as its own attacks where there is no evidence of a connection".
Its ever-shrinking circle of influence means it is "more important than ever to project an image of a powerful organisation with global reach", even when there is no proof of any direct involvement, he adds.
Prime Minister Theresa May says the attack, coming on the heels of Westminster and Manchester, was evidence that "terrorism breeds terrorism".
Metropolitan Police Commissioner Cressida Dick told BBC Breakfast this morning there was a "possibility" that the Manchester attack had acted as inspiration for the London knifemen, although it was not believed the two had any direct link.
"The rhetoric coming from Daesh [Islamic State] and other organisations has been to encourage people to take action into their own hands, to use low-tech methods," she added.
"Undoubtedly when people see something which appears from their perverted point of view to be successful, some people will be inspired by that. So that is a possibility."
Seven people died and dozens were wounded in Saturday night's attack, in which a white van ploughed into pedestrians on London Bridge before the three men inside began stabbing revellers in nearby pubs and restaurants.
Canadian Christine Archibald is the first victim to be identified, with the dead and injured said to include people from Australia, New Zealand, France, Spain and Greece. Four police officers were also among the wounded.
Of the 48 people taken to hospital, 21 are still in a critical condition.
London Bridge attack: 'Enough is enough,' says Theresa May, after seven are killed
Theresa May has said the UK must change the way it deals with extremism after seven people were killed and 48 injured following a terrorist attack in central London last night.
"There is, to be frank, far too much tolerance of extremism in our country," she said this morning from Downing Street, adding that "preachers and supporters of hate" must no longer be allowed "safe spaces" either online or in the real world.
"We cannot and must not pretend that things can continue as they are," she said. "Things need to change."
How the London Bridge attack unfolded
A van was driven into pedestrians on London Bridge at 10.08pm followed by reports of people being stabbed in nearby Borough Market, an area packed with bars and restaurants. The Metropolitan Police said armed officers responded and opened fire.
Police declared the incident a terrorist act soon after midnight.
BBC London reporter Holly Jones, who was on the bridge when the attack began, said a white Transit van travelling at about 50mph had been driven on to the pavement. "He swerved right round me and then hit about five or six people," she said. "He hit about two people in front of me and then three behind."
Police were on the scene in two minutes and ambulances arrived in six to eight minutes, added Jones.
"One cab driver said three men ran towards the market stabbing people - including a young girl - as they ran," says the Daily Telegraph. "One eyewitness spoke of the men shouting 'this is for Allah' as they stabbed indiscriminately."
Several witnesses said they were locked inside buildings for their own safety. Armed officers flooded the area and footage posted online showed police inside one restaurant ordering diners to lie on the ground.
"The knifemen ran shouting into the El Pastor taco restaurant in Borough Market and stabbed a woman," the Sunday Times reports. "Witnesses said diners threw chairs and other objects at the attackers and drove them out."
Assistant Commissioner Mark Rowley of the Metropolitan Police said the attackers were "wearing what looked like explosive vests but these were later established to be hoaxes".
He added: "The suspects had been confronted and shot by the police within eight minutes of the first call."
Police boats searched the Thames for pedestrians who may have been thrown into the water and a helicopter was seen flying over the bridge. According to the Telegraph, "SAS forces have been deployed in central London".
Five hospitals are treating the casualties, who include a British Transport Police officer who suffered serious but not life-threatening injuries.
Police say they believe the attackers were killed at the scene.
London Mayor Sadiq Khan called the incident a "deliberate and cowardly attack on innocent Londoners and visitors to our city enjoying their Saturday night", while Prime Minister Theresa May said that along with the Manchester Arena suicide bombing two weeks ago and the Westminster Bridge attack in March, it was part of "a new trend in the threat we face as terrorism breeds terrorism".
Saying the attacks were connected by the "single evil ideology of Islamist extremism", she added that "difficult and often embarrassing conversations" would be necessary to defeat it.
"The whole of our country needs to come together to take on this extremism and we need to live our lives not in a series of separated, segregated communities, but as one truly United Kingdom," she said.
May also chaired a meeting of the government's Cobra committee, although Amber Rudd, the Home Secretary, told ITV's Peston on Sunday that the Joint Terrorism Analysis Centre had recommended no change to the threat level, which is at "severe", the second-highest level, after being reduced from "critical" in the days after the Manchester attack.
Labour and the Conservatives have suspended national campaigning, but the Prime Minister said they would resume a full schedule tomorrow. Thursday's general election will go ahead as planned.
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