A man wielding a large knife who allegedly lunged at shoppers and chased unarmed police in a northwestern England mall was arrested overnight on suspicion of terrorism.
Five people were hurt, three of whom needed hospital treatment for stab wounds, and the 41-year-old suspect was detained.
Police do not believe anyone else was involved in the attack at the Arndale Centre in Manchester.
"We do not know the motivation for this terrible attack," Greater Manchester Police Assistant Chief Constable Russ Jackson said. "It appears random, is certainly brutal and of course extremely frightening for anyone who witnessed it."
Jackson said the incident was "bound to bring back memories of the awful events of 2017," when 22 people were killed after a suicide bomber targeted a concert by pop star Ariana Grande at Manchester Arena, a venue only few hundred metres away.
The Manchester Arena bombing caused widespread anguish in part because so many of the dead and wounded were young fans of Grande, a pop star with massive following among teenage girls.
Witnesses of last night's attack described the distress of terrified shoppers sheltering in stores. Unarmed community support officers challenged the suspect, but were chased as they called for backup. Armed and unarmed officers responded within five minutes.
Freddie Houlder, 22, was at the centre when he heard "a load of screams just outside" the shop he was in. A woman came in and told others that "a guy just ran past the shop and tried to stab me."
"Luckily she had quite a thick jacket — she thought originally it was a fake knife because of how easily it grazed off," he said. "But police came in and said it was a real knife and she burst into tears."
The suspect was originally detained on assault charges but was later arrested on a charge of "the commission, preparation and instigation of an act of terrorism."
Prime Minister Boris Johnson said he was "shocked by the incident," adding: "My thoughts are with the injured and all those affected."