A rise in violence is "almost inevitable" because of the coronavirus lockdown, a police and crime commissioner warned as a series of stabbings left one dead and seven injured in Birmingham.
The attacks happened at four Birmingham locations over a period of 90 minutes.
He said many people had been seated at outdoor tables eating and drinking on Saturday evening.
"At this stage we believe that the attacks were random and we have no indication of a motive".
Police said they were hunting for a lone male suspect over the apparently random attacks in the city centre early on Sunday morning.
The incident comes after several previous mass casualty stabbings, including one in the Scottish city of Glasgow on June 26, in which six people were injured, including a police officer.
A police officer and vehicles are seen at a cordon in Irving Street in Birmingham after a number of people were stabbed in the city centre, Sunday, Sept. 6, 2020.
- A total of seven patients were treated by ambulance staff - five of which were taken to the major trauma centre at Queen Elizabeth Hospital Birmingham.
"One line of inquiry ultimately led us to an address in the Selly Oak area this morning where a man was arrested".
He said the incident followed a surge in violent crime across the region over the past weeks and months.
Police are still encouraging any witnesses to call the hotline or send in video footage or photos of the incidents or the attacker.
It said emergency services were working together at the scene, and making sure that those who were injured received medical care. "Our thoughts and prayers are with the victims and their families".
But she urged local residents to "refrain from sharing speculation online about the incident as investigations are still ongoing".
But the force is also facing criticism of their response to the attacks, including why the man was allowed to wander the city for as long as he did.
British police have launched a murder investigation after the stabbings.
The stabbings took place between 23:30 and 01:20 GMT.