A man in his 40s was arrested on suspicion of committing terror offenses after a Friday morning stabbing attack at a shopping mall in Manchester, in northern England.

Police said three victims — two women and a man — were taken to the hospital with stab wounds and a fourth person was treated at the scene.

Authorities have not named the suspect nor described his possible motives or affiliations. They said he appeared to have acted alone.

Greater Manchester Police’s assistant chief constable, Russ Jackson, said the suspect is believed to be a British citizen from the Manchester area.

“We do not know the motivation for this terrible attack. It appears random, is certainly brutal and of course extremely frightening for anyone who witnessed it,” Jackson told reporters.

Jackson said the stabbing attack, deemed a terrorism offense, “was bound to bring back memories of the awful events of 2017,” when a radical Islamist killed 22 people and injured hundreds more at pop singer Ariana Grande’s concert at Manchester Arena. Suicide bomber Salman Abedi died in that attack; his brother is on trial for conspiring to cause the blast.

Armed police surround the Arndale shopping center, where a man stabbed five people on Oct. 11, in Manchester, England. (Anthony Devlin/Getty Images)

Greater Manchester Police said they were alerted to reports of stabbings at Arndale shopping center in Manchester city center at 11:17 a.m. local time on Friday.

“Given the location of the incident and its nature, officers from Counter Terrorism Police North West are leading the investigation as we determine the circumstances,” police said. Britain’s MI5 service, the domestic counterintelligence and security agency, is also monitoring the case.

Witnesses at the shopping center told Britain’s PA Media that a man tried to slash people, seemingly at random.

A shop worker, who identified himself only as Jordan, 23, told the news agency, “A man was running around with a knife lunging at multiple people, one of which came into my store visibly shaken with a small graze.”

Jordan said, “Soon after, security staff told all retail staff to close their doors and move the public to the back of the stores.”

Freddie Houlder, 22, was in the Arndale mall when he heard “a load of screams just outside” the store he was in.

Houlder told PA Media that a woman came into the shop and told others that “a guy just ran past the shop and tried to stab me.”

Houlder said, “Luckily she had quite a thick jacket — she thought originally it was a fake knife because of how easily it grazed off, but police came in and said it was a real knife and she burst into tears.”

Jackson said two unarmed police officers confronted the attacker, who chased them with the knife.

Images on social media showed a man in a puffer jacket on the ground, with one police officer holding his wrists and a second officer standing over him with a stun gun.

The mall has undergone major renovations since 1996, when it was damaged following an attack in which the Irish Republican Army detonated a 3,300-pound device nearby.

Prime Minister Boris Johnson said he was “shocked” by the stabbings. “Thank you to our excellent emergency services who responded and who are now investigating what happened,” Johnson tweeted.

Karla Adam contributed to this report.