Several people have been injured after a van struck a crowd of pedestrians near a north London mosque in what police have called a "major incident".
One person was arrested following the collision near Finsbury Park Mosque in Seven Sisters Road.
Officers were called at 00.20 BST and remain at the scene, the Metropolitan Police said.
The Muslim Council of Britain (MCB) said a van "intentionally" ran over worshippers.
Many of the victims are believed to have just left evening prayers after breaking the Ramadan fast.
London Ambulance Service said it had sent "a number of resources" to the scene.
Video posted online of the aftermath showed a scene of chaos as people tried to help the injured.
One man could been seen giving CPR to a victim in the street while another man's head injury was treated with a makeshift dressing.
One eyewitness who lives in a flat on Seven Sisters Road told the BBC she saw people "shouting and screaming".
"Everyone was shouting 'a van's hit people'.
"There was this white van stopped outside Finsbury Park Mosque that seems to have hit people who were coming out of the mosque after prayers finished."
She said the road was "backed up" with police cars, ambulance and fire engines.
London Ambulance Service deputy director of operations Kevin Bate said: "We have sent a number of ambulance crews, advance paramedics and specialist responses teams to the scene.
"An advance trauma team from London's Air Ambulance has also been dispatched by car.
"We are working closely with other members of the emergency services at the scene.
"Our priority is to assess the level and nature of injuries and ensure those in the most need are treated first and taken to the hospital."
Witness Cynthia Vanzella said on Twitter: "Horrible to watch police officers doing cardiac massage at people on the floor, desperately trying to save them. I just hope they did."