Police have praised members of the public who helped detain a suspect after a shopper and a member of staff were stabbed at a branch of Marks & Spencer store in Burnley.
Lancashire Police said they were called to the store in St James's Street at around 9.30am where they discovered two women suffering from stab wounds.
They arrested a 57-year-old man at the scene on suspicion of attempted murder.
Police said witnesses to the incident had acted quickly and without thought for their own safety by helping to restrain the suspect until officers arrived.
Footage posted on social media showed the police detaining a middle aged Muslim man, who was wearing a facemask, outside the store.
A force spokesman said it was not being treated as a terrorist incident, although counter terror police were leading the investigation due to comments that had been made at the scene.
It is understood police are looking into whether the suspect's mental health may have played a part in the incident.
The two victims, a member of staff in her 40s and a shopper in her 60s, were rushed to hospital where their injuries were described as serious but not life threatening.
A large cordon was in place around the town centre, where many of the businesses had just reopened after the end of the lockdown.
The suspect appeared calm as he was being handcuffed by officers.
Police said they were treating it as an "isolated incident" and they were not looking for anyone else in connection with the stabbing.
Superintendent Stasia Osiowy, said: "We recognise that this incident will have caused a great deal of concern in the community and I would like to reassure people that we have a dedicated team of officers and staff carrying out enquiries and a number of extra patrols in the town centre as reassurance.
"We have arrested a man and we will be speaking to him in due course as part of our ongoing investigation.
"This is not being treated as a terrorism incident but due to some comments made at the scene counter-terrorism detectives will be leading on the investigation.
"At this time we are keeping an open mind as to motivation but what I can say is that we are considering the mental health background of the man we have arrested.
"I would like to appeal to members of the public who may have seen or filmed this morning's incident, or who have information which could assist, to get in touch with us.
"I would like to thank those members of the public who acted very quickly, and without regard to their own safety, this morning in order to detain the attacker.
"Without their brave actions this incident, while serious, could have been so much worse."