A knife-wielding man was arrested in London after repeatedly stabbing a mosque elder as he led Thursday afternoon prayers, according to police and the mosque.

The unidentified victim, in his 70s, is London Central Mosque’s muezzin — the person who makes the call to worship — and had started leading the Asyr Prayer when he was attacked, the mosque said.

Witnesses told London’s Evening Standard that he was stabbed in the shoulder as soon as prayers started, while other reports said he had also been stabbed in the neck.

The attacker was tackled by worshipers and held until police arrived, the mosque said.

A shoeless man in a red top was shown being pinned down inside the religious building while surrounded by shocked worshipers, including at least one child, in photos from the scene. One video showed a knife on the floor under a plastic chair, the Standard said.

London’s Met police said a man was arrested on suspicion of attempted murder. He had yet to be identified Thursday afternoon and police had yet to suggest a possible motive.

The victim was treated by paramedics at the scene before being taken to a local hospital. “His condition has been assessed as non-life-threatening,” police said in a statement.

The mosque stressed that while he “did not sustain any life-threatening injuries,” he was still “seriously injured” and remains in a hospital.

“We await further information from the police regarding the incident, our thoughts and prayers are with the Muazzin and his family,” the mosque said.

A witness told the Standard that the suspect had been a regular at the mosque, and he appeared to wait for prayers to start to pounce.

“It has just started and he was waiting for them to start. He was praying behind him and then he stabbed him,” Abi Watik, 59, told the paper, saying the attacker had been “silent the whole time.”

Prime Minister Boris Johnson said his thoughts were with the victim and “all those affected.”

“I’m deeply saddened to hear of the attack at the London Central Mosque. It’s so awful that this should happen, especially in a place of worship,” he tweeted.

With Post wires