Counter-terrorism police are leading an investigation into a series of stabbings at the Arndale shopping centre, Greater Manchester police have said.
The shopping centre has been evacuated and trams have stopped operating at Exchange Square outside the entrance.
Police said there had been no reports of fatalities and counter-terror officers were leading the investigation but “keeping an open mind”.
A man in his 40s has been arrested on suspicion of serious assault.
A spokesperson for Greater Manchester Police said: “We can confirm that five people have been stabbed and taken to hospital.
“In these early stages, we are keeping an open mind about the motivation of this terrible incident and the circumstances as we know them.
“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.”
Social media posts have shown a large number of officers at the scene and the suspect being Tasered.