The Muslim Council of Britain has condemned the Finsbury Park van attack, calling it "the most violent manifestation" yet of Islamophobia and calling for extra security around mosques.
The council's secretary general Harun Khan says the incident took place outside the Muslim Welfare House in Seven Sisters Road.
He said: "According to eyewitness accounts and videos taken after the incident, it appears that a white man in a van intentionally ploughed into a group of worshippers who were already tending to someone who had been taken ill.
"We do not know how many were injured or killed, but our prayers are with the victims and families.
"During the night, ordinary British citizens were set upon while they were going about their lives, completing their night worship. It appears from eyewitness accounts that the perpetrator was motivated by Islamophobia.
"Over the past weeks and months, Muslims have endured many incidents of Islamophobia and this is the most violent manifestation to date.
"Given we are approaching the end of the month of Ramadan and the celebration of Eid with many Muslims going to local mosques, we expect the authorities to increase security outside mosques as a matter of urgency.
"Muslim communities have been calling for increased action to tackle the growth in hate crime for many years and transformative action must now be taken to tackle not only this incident but the hugely worrying growth in Islamophobia.
Many will feel terrorised, no doubt be angry and saddened by what has taken place tonight.
"We urge calm as the investigation establishes the full facts, and in these last days of Ramadan, pray for those affected and for justice."
Mohammed Shafiq of the Ramadhan Foundation, a Muslim organisation which speaks out against extremism, said: "I utterly condemn the senseless and evil van attack against Muslim worshippers outside the Finsbury Park Mosque in London.
"According to eyewitnesses this was a deliberate attack against innocent Muslims going about their life.
"We should make clear that if this attack is confirmed as a deliberate terrorist attack then this should be classed as an act of terrorism.
"The British Muslim community requires all decent people to stand with us against this evil violence.
"Rampant Islamaphobia has been on the rise for a number of years and those on the far right have perpetuated hatred against Muslims.
"They should be called out for their hatred."