The man suspected of deliberately driving a van into a crowd of worshippers outside a mosque has been identified as Darren Osborne, a 47-year-old father of four.
Mr Osborne was arrested on suspicion of attempted murder and alleged terror offences.
Police officers stand guard outside a residential property in Cardiff, south Wales as investigations continue into the attack.
A vehicle struck pedestrians near a mosque in north London early Monday morning, causing several casualties, police said.
A man intent on killing Muslims plowed a rented van into the group of Londoners - killing one and injuring 10 more - before jumping out and taunting them with slurs, according to witnesses.
Photos show a number of police cars are on the scene and the area cordoned off to civilians.
Prime Minister Theresa May said she would chair an emergency security Cabinet session later Monday.
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The value of each Lok Sabha and Rajya Sabha MP's vote is 708 and value of vote of MLAs is decided by population of that state. The Shiv Sena had earlier said it may choose an "independent" path in the election to the highest constitutional office.
Metropolitan Police said they were dealing with a "major incident".
One man, who was already ill and receiving CPR on the side of the road as the attack occurred, passed away after the incident. Three Muslim extremists who carried out the attack were killed by police.
Police said a suspect was quickly and calmly turned over to the police, and that no one else was found in the van.
The Muslim worshippers were helping an elderly man who had fallen down in the street.
"We stopped all forms of attack and abuse towards him that were coming from every angle".
On March 22, a man drove a rented vehicle into pedestrians on Westminster Bridge in London and stabbed a policeman to death before being shot dead.
"We saw lots of people shouting and lots of people injured", David Robinson, 41, who arrived just after the accident, told AFP.
Khan told Sky News that Mahmoud's actions "calming things down" were "what I'd expect from a good faith leader, from a good Muslim leader".
Sarah Mushtaq said attacks like what happened in London can create some fear within the Muslim community in Windsor. In addition to the attackers, seven people are killed and dozens of others wounded.