The man suspected of having stabbed two people to death in London on Friday before being shot dead by police was identified by authorities as 28-year-old Usman Khan, who had previously been convicted for terror offences.
A man and a woman died during the attack on London Bridge, police said in the early hours of Saturday.
A man and two women, were also injured and remained in hospital. Police are treating the case as a terrorist incident.
“This individual was known to authorities, having been convicted in 2012 for terrorism offences,” Neil Basu, head of Britain’s counterterrorism policing, said in a statement.
“He was released from prison in December 2018 on licence and clearly, a key line of enquiry now is to establish how he came to carry out this attack,” he said, adding that officers were carrying out searches at an address in Staffordshire, the area where the suspect had been residing.
Basu said that police were not actively seeking anyone else in relation to the attack.
Extensive cordons were “likely to remain in place for some time,” Basu added, asking the public to continue to avoid the area.
London Mayor Sadiq Khan tweeted that during the weekend there would be “enhanced police patrols, including firearms teams, on the streets of London”.
The suspect, who was shot dead by specialist armed officers, was wearing a “hoax explosive device,” Basu had said earlier.
He said police were called just before 2 pm (1400 GMT) “to a stabbing at a premises near to London Bridge.”
“A male suspect was shot by specialist armed officers from City of London Police and I can confirm that this suspect died at the scene,” he said.
According to the counterterrorism policing head, the attacker attended an event earlier on Friday afternoon at Fishmongers’ Hall, a historic building on the bridge.
“We believe that the attack began inside before he left the building and proceeded onto London Bridge, where he was detained and subsequently confronted and shot by armed officers,” Basu said.
British media had reported that the suspect had a criminal record and connections to Islamist terror groups, with newspaper the Times reporting that he was wearing an electronic tag monitoring device.
Prime Minister Boris Johnson, speaking before chairing a meeting of the British Government’s emergency committee Cobra which the London mayor would also attend, had hinted that the suspect had a record.
“(It is a) mistake to allow serious and violent criminals to come out of prison early and it is very important that we get out of that habit and that we enforce the appropriate sentences for dangerous criminals, especially for terrorists,” PA cited him as saying.
Police called for the public to send in footage and pictures of the incident as it appealed to “use common sense and restraint” in sharing the content online.
Some social media users had posted footage of armed police “apparently pulling civilians off a person lying on the ground on the bridge before firing at him from close range,” The Guardian reported.
BBC reporter John McManus said he saw a “fight” on the bridge, with several people attacking one man until police arrived and fired several shots at the man.
In June 2017, three men drove a van into pedestrians on London Bridge, before stabbing people at bars and restaurants in the nearby Borough Market. Seven people died in the attack.
In a separate incident, a man stabbed and injured three people in the centre of The Hague on Friday, Dutch police said on Twitter.
Medical response officials rushed to the scene at the Grote Marktstraat, a busy shopping street in the city centre, the ANP news agency reported.
The attacker fled and a manhunt began.
Police said there were no signs of a terrorist motive, but would keep investigating all possibilities.