Britain's
Boris Johnson said Sunday the security services were stepping up monitoring of convicted terrorists released early from prison, as the
London Bridge attack became embroiled in the
election campaign.
The prime minister revealed officials were scrutinising 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.
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-offender event that also left three people injured.