Prime Minister Theresa May says the terror attack near a north London mosque is "every bit as sickening" as recent attacks to hit the UK, reports BBC.
She was speaking after a man died and 10 people were injured when a man drove a van into worshippers near a north London mosque.
Eight people were taken to hospital after the attack outside the Muslim Welfare House.
A 48-year-old man has been arrested on suspicion of attempted murder.
A group of people were helping a man who had collapsed when they were hit by the van just after midnight. The man has died, but it is unclear whether this was as a result of the attack.
Police said all the victims of the attack, which was in the area of Finsbury Park Mosque, were Muslim.
May said the driver of the fan acted alone, adding: "Hatred and evil of this kind will never succeed."
She also said that police declared it a terrorist incident within eight minutes.
She added that "there has been far too much tolerance of extremism over many years".
Eyewitness Abdul Rahman said the driver had said he wanted to "kill all Muslims" and told the BBC he struck the man and helped subdue him..