Muslim leaders have described the Finsbury Park van attack on worshippers as "senseless and evil".
One has died and 10 others were injured after a white van was driven into a crowd near a mosque in the early hours of Monday morning.
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."
The Muslim Council of Britain (MCB) general secretary Harun Khan said: "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."
Chairman of the mosque at Finsbury Park Mohammed Kozbar tweeted: "Our thoughts and prayers with those who got injured and effected by this cowardly attack in Finsbury Park area, many casualties in the floor."