Police have not released the identity of the third.
It had been set at "critical" in the days after the Manchester concert bombing on May 22 that killed 22 people - reflecting a judgment that an attack might be imminent because accomplices with similar bombs might be on the loose.
At a press conference she defended her policies when questioned on cuts of 20,000 police officers, and on control orders being watered down. President Donald Trump has also been briefed.
"Last week he called for a barbecue and invited all of us". In a letter posted outside his gym, the Ummah Fitness Centre said staff would "help the police in any way we can".
Mark Rowley, the Metropolitan Police assistant commissioner, outlined his plan to radically improve counterterrorism capabilities in the wake of the London Bridge attack on Saturday in which seven people died and 48 were injured.
Jeremy Corbyn, leader of the main opposition party, called on May to resign over the issue, saying earlier that "you can not protect the public on the cheap", and promising to recruit another 10,000 police officers if he is elected into power.
May hailed police actions in response to Saturday's attacks, which she said "saved countless lives", but said, "We have seen overall too much tolerance of extremism in this country", and repeated her call for a commission to take up "the necessary task of stamping out extremism".
The latest opinion poll, by Survation for ITV, showed the Conservatives' lead narrowing to just one point from six points in the same poll a week earlier.
Echeverria's family explained that he was probably not carrying any identification at the time of the attack, and although they know he is not among the seven fatalities, they have been unable to get confirmation as to whether or not he was injured.
Her family said in a statement: "We grieve the loss of our handsome, loving daughter and sister".
Her family urged people to honour her memory by "making your community a better place". "Volunteer your time and labour or donate to a homeless shelter", they said in a statement. Officials at the scene told the paper that it was suspected that Butt had been radicalized in the United Kingdom, rather than Pakistan, but they were searching relatives' houses as a precautionary measure. The men mowed down pedestrians using a vehicle, and then began attacking them with knives.
The Islamic State terror group, also known as Daesh, has claimed responsibility for the London Bridge rampage, while the attack has sparked fears Britain is in the grip of a spate of copycat incidents.
Police on Tuesday were facing questions over how one of the London Bridge attackers slipped through the net as British Prime Minister Theresa May continued to come under attack over police funding cuts. Both the Westminster and Manchester attackers were British-born.
The violence came less than a week before Britain's parliamentary elections.
Christine Archibald, the Canadian woman who was killed in the London Bridge terror attack on the weekend, was a gentle soul with a depth of sensitivity that made her a great social worker, her former Calgary boss recalled Monday.
But that did not stop the questions to May about police numbers during her time as interior minister. The number of authorised firearms officers in England and Wales fell to just under 5,700 in 2016 from almost 7,000 in 2010.
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