LONDON (AFP) -- Britain's Boris Johnson said he had ordered the security services to step up monitoring of convicted terrorists released early from prison, prompting accusations that he was exploiting the London Bridge attack for political gain less than two weeks before elections.
The prime minister revealed officials were scrutinizing around 74 people with terrorist convictions who had been released early from prison like Usman Khan, who left jail last December and went on to stab two people to death in Friday's rampage.
"They are being properly invigilated to make sure there is no threat," Johnson told the BBC. "We've taken a lot of action as you can imagine in the last 48 hours."
Under the review of released terror convicts, police in the West Midlands said they had arrested a 34-year-old man "on suspicion of preparation of terrorist acts".
British media said he was a former associate of the London Bridge attacker and had been jailed alongside Khan in 2012 over a plot to bomb the London Stock Exchange.
Police said, however, there was no information to suggest a link to Friday's attack.
Khan, 28, was shot dead wearing a fake explosives vest by police on London Bridge after a stabbing spree launched in a nearby hall hosting an ex-offenders' event that also left three people injured.
Police on Sunday formally named the two victims killed as Jack Merritt, 25, from Cambridgeshire in eastern England, and 23-year-old Saskia Jones of Warwickshire in the West Midlands.
Johnson blamed the previous Labour government for changing the law in 2008 to allow for the early release of prisoners and vowed to introduce minimum 14-year sentences if he regains power in the December 12 vote.
He penned an article setting out the new stance in The Mail on Sunday newspaper, under the headline: "Give me a majority and I'll keep you safe from terror".
Critics hit out at him for appearing to politicize Friday's attack -- including the family of victim Jack Merritt, who said he died "doing what he loved".
Meanwhile, hospital officials said one of the injured had returned home, while the two others remained hospitalized in a stable condition.
Members of the public have been hailed as heroes for preventing even greater loss of life by tackling Khan -- one armed with a five-foot (1.5-metre) narwhal tusk and another with a fire extinguisher.
The incident came two years after Takfiri extremists in a van ploughed into pedestrians on London Bridge before attacking people at random with knives, killing eight people and wounding 48.