A man has been arrested on suspicion of attempted murder after four people, including a policeman, were stabbed at a mosque in Birmingham.
Officers were called to the mosque on Washwood Heath Road in Ward End at about 23:00 BST on Saturday.
West Midlands Police said three men were found with stab injuries.
The officer was wounded as police arrested the 32-year-old man who has since been taken to a secure mental health unit.
A police spokesman said: "The suspect was assessed by mental health expert and was deemed unfit to be interviewed.
"The man will be constantly assessed by medics who will alert detectives as soon as he is deemed well enough to undergo questioning."
The officer, aged 31, and a 28-year-old man suffered multiple stab wounds while a 36-year-old man sustained a single stab wound to his leg. All three were taken to hospital.
Another victim is recovering at home after injuring his hand.
The incident began during the final prayer session of the evening.
Ch Supt Alex Murray said the man they arrested was of Somalian descent and that a "sizeable knife" had been used in the attack.
Mr Murray said officers arrived at the mosque within four minutes of reports of the stabbings.
The suspect was found in a room in the mosque but when challenged he ran at one of the two police officers.
The officer, who suffered chest and stomach injuries, fired a Taser at the knifeman but it did not halt him, Mr Murray said.
"The individual was worshipping but not known to the mosque," he added, before thanking and reassuring the local community.
Dr Arshad Mahmood, who was at the mosque, said: "A man started stabbing one of the guys who was just sitting right next to him.
"I don't know what exactly was the reason but he just started stabbing him.
"We went to save him. He had multiple injuries, three or four wounds.
"Then the policeman came and was also attacked and stabbed."
Mohammed Shafiq, the leader of national Muslim organisation the Ramadhan Foundation, said his thoughts were with the injured and their families.
"I have spoken to someone who lives a few doors down from the mosque and they described hearing an argument between some of the people inside.
"It escalated into violence and a police officer has been stabbed."
According to Mr Shafiq, a nearby resident believed the dispute was a domestic incident between mosque members.
The mosque involved is the Washwood Heath Muslim Centre in Ward End.
The Birmingham Hodge Hill MP Liam Byrne, who visited the scene, said: "Police and the community have been working together through the night and early this morning and what's very clear is that this is a sad, tragic and isolated incident.
"It's not a hate crime.
"What's really important now is that everybody stays very calm and we let the wheels of justice turn."
Ansar Ali Khan, the city councillor for Washwood Heath, said people will have been attending the mosque for local prayers.
"We've never had a problem, we always have a very peaceful situation in this area," he said.
"This is shocking for me to know the police officer has been stabbed as well."