One killed, ten injured in 'horrific terrorist incident' targeting worshippers near London's Finsbury mosque
Home Secretary Amber Rudd said police were treating the incident as a "terrorist incident".
A police statement said "One man was pronounced dead at the scene... Eight people injured were taken to three separate hospitals."
Two others were treated at the scene for light injuries.
A police statement confirmed all the victims of the attack were identified as Muslims who were visiting the mosque for Taraweeh prayers during the fasting month of Ramadan.
The male driver of the van had also been taken to hospital as a precaution and would receive a mental health assessment, the police said.
The 48-year-old driver was detained by members of the public before police arrived on the scene shortly after the attack.
Witness Abdiqadir Warra told AFP the van "drove at people" and some of the victims were carried for several metres along the road.
One witness, Abdul Rahman, told the BBC he saw the van "deliberately run over about 10 or 15 people". Rahman said he and another man wrestled the suspect to the ground and held him down for 20 to 30 minutes before police arrived.
Amateur video footage seen by AFP showed at least three people lying on the ground, including one who was receiving mouth-to-mouth resuscitation.
"Due to the nature of this incident, extra policing resources have been deployed in order to reassure communities, especially those observing Ramadan," the police statement said.
Muslim leaders said worshippers were specifically targeted after leaving prayers near Finsbury Park mosque in north London shortly after midnight, and linked the incident to a recent rise in anti-Muslim hate crime.
The Muslim Council of Britain (MCB), an umbrella body for British Muslims, said the incident occurred outside the Muslim Welfare House on Seven Sisters Road.
"Over the past weeks and months, Muslims have endured many incidents of Islamophobia and this is the most violent manifestation to date," MCB head Harun Khan said.
London Mayor Sadiq Khan said the incident was a "horrific terrorist attack," calling it "deliberate" and aimed at "innocent Londoners, many of whom were finishing prayers during the holy month of Ramadan".
Prime Minister Theresa May is expected to chair an emergency ministerial meeting later on Monday to discuss the attack.