A gun was fired outside a mosque in east London during Ramadan prayers, ONA reports citing BBC.
Police were called to reports of a man with a firearm entering the Seven Kings Masjid in Ilford on Thursday night.
Worshippers ushered him out of the building and a gunshot - thought to have come from a "blank-firing handgun" - was then heard.
No injuries or damage were caused, Scotland Yard said, and it did not believe the incident was terrorism-related.
Evening prayers were being held at the mosque, off High Road, at the time.
The Met Police said: "Officers, including firearms officers, attended. There were no reported injuries or damage to the building.
"At this early stage, ballistic evidence recovered from the scene suggests that the weapon was a blank-firing handgun."
Officers will remain at the scene overnight, it added.
In a statement shared by a Muslim Council spokesman on Twitter, the mosque's imam Mufti Suhail said the suspect's motives had not been established.
He asked that people "avoid speculating and circulating unconfirmed information".