06 June, 2017
In Britain's third Islamist attack in as many months, three men on Saturday rammed a van into pedestrians on London Bridge before running into the Borough Market area, where they slit throats and stabbed people indiscriminately.
London Police Chief Cressida Dick said that while some of the recent attacks in Britain had global links, they had a largely domestic centre of gravity.
Butt was previously known to police and domestic spy agency MI5 and was a British citizen who had been born in Pakistan, the police said.
"However, there was no intelligence to suggest that this attack was being planned and the investigation had been prioritized accordingly", police said.
The other attacker, Rachid Redouane, 30, claimed to be Moroccan-Libyan descent, also lived in the same area of east London.
Police said Redouane also used the name of Rachid Elkhdar and a different date of birth that gave his age as 25.
She confirmed that police have foiled five plots since the Westminster attack in March and 18 in the last four years that "we knew were created to cause mayhem, murder, destruction".
Metropolitan Police Commissioner Cressida Dick said she wouldn't release further details in what she described as a fast-moving investigation. Two people were detained as a result of the action.
Police attend to an incident on London Bridge in London June 3, 2017.
"We have made a number of arrests, we are trying to find out whether anyone was helping them and to understand the background to this attack as best we possibly can", she said speaking to Sky News.
Police said they had to prioritise resources on suspects who were believed to be preparing an attack or providing active support for one.
The first victim of the attack has been named as Canadian national Christine Archibald, who worked in a homeless shelter until she moved to Europe to be with her fiance.
Butt, along with two others, are responsible for at least seven deaths after ramming a van into civilians atop London Bridge before embarking on a brutal stabbing spree.
But she said Britain was under threat from a new breed of crude copycat militants who might not have spent years plotting or even been radicalised online.
On Twitter, President Donald Trump called out Mayor Khan for telling the public that there was "no reason to be alarmed" after the attack, seemingly taking the mayor's message out of context.
They would've known full well that attacking people in the street would draw armed police in their direction and the fake bomb belts they were wearing would, in their own warped minds, hasten their demise.
Scotland Yard Commissioner Cressida Dick said authorities were confronting a "new reality" after three deadly assaults hit the United Kingdom in 10 weeks.
"We grieve the loss of our handsome, loving daughter and sister who was 30 years old".
Armed police arrived and shot the attackers dead within eight minutes of the first emergency call.
It was not immediately clear how the attack would impact the election.
The country's major political parties temporarily suspended campaigning with only days to go before Thursday's general election.
A friend of one of the attackers also told the BBC Asian Network he had reported him to the anti-terror hotline after he began expressing increasingly radical views and justifying terror attacks, but the man said he was never arrested.
