A 48-year-old man has been arrested and is in custody. He will be given a mental health evaluation.
"There'll be a zero tolerance toward hate crime", Mr Khan said.
The driver of the van has reportedly been arrested.
Witness Hussein Ali said a crowd had gathered around the attacker before the leaders of the mosque stepped in and told others "you don't touch". One man died at the scene, although he was receiving first aid at the time and it wasn't clear if he died as a result of the attack or from something else. If British authorities can't prove that they are capable of handling the ongoing threat from ISIS among Britain's own Muslim citizens-and given the flood of British ISIS fighters returning home, it's unlikely they'll be able to-we can expect more of these "counter-attacks" on British Muslims.
Eyewitnesses reported seeing police give emergency heart massage to at least one of the injured.
"Over the past weeks and months, Muslims have endured many incidents of Islamophobia and this is the most violent manifestation to date", said Harun Khan, head of the Muslim Council of Britain, an umbrella body.
President Trump has taken to Twitter during previous terror attacks to make the case for tighter restrictions on travel from predominantly Muslim countries.
A police forensics officer stands next to a van believed to be involved in the incident near Finsbury Park Mosque.
The next day, Osborne repeated the insult to her 10-year-old daughter, Sherizi said.
London police closed the area to normal traffic. May vowed to provide extra police resources to protect mosques.
The van driver tried to escape but people grabbed him. It seems likely that Osborne chose this mosque intentionally, although we won't know for sure until he has been interviewed and more information is released.
Prime Minister Theresa May on Monday called the incident a "terror attack" and "every bit as sickening" as recent attacks to hit the United Kingdom, adding that the driver acted alone. British media reported that there was no evidence Osborne belonged to any far-right organization and said he was not known to the security services.
Video posted on social media appears to show police and bystanders surrounding an injured person on the ground after a van ploughed into worshippers near a London mosque.
Britain's terrorist alert has been set at "severe", meaning an attack is highly likely.
Mr Mahmoud claimed that two people were dragged under the van, adding that he feared one may be "paralysed for life".