London police closed the area to normal traffic. Muslims now are observing Ramadan, during which they fast from dawn to dusk and engage in intense prayer and feast at sundown. A van left the roadway and swerved into a large crowd standing on the sidewalk, witnesses reported.
"There are a number of casualties", the police said in an earlier statement.
The person who died was the same elderly worshipper people had been giving first aid to before the attack. Nearly, a man held a bloody cloth to his head.
The Met said: "At this early stage of this investigation, no other suspects at the scene have been identified or reported to police, however the investigation continues".More news: UK royals hold London fire minute of silence
In a statement, the police say they were called to the Seven Sisters Road by reports of collision with pedestrians. "I could see at least two people on the floor not moving and police officers trying to do cardiac massage on them", Vanzella said.
"Everyone was shouting "a van's hit people".
Another shocked witness told the Press Association he jumped out of the van's path as it ploughed into conversing bystanders.
"They were very nervous, shouting very loud, trying desperately to make some signs to a police vehicle that was just passing the road", she told CNN.
"He tried to kill a lot of people so obviously it's a terrorist attack".
"There were bodies around me".More news: Champions League glory a huge step for Madrid youngster Asensio
He added: "Thank God I just moved to the side, I just jumped".
Finsbury Park is a diverse London suburb situated a few kilometres north of the city centre.
Finsbury Park Mosque has undergone wholesale changes and become far more liberal under new leader Mohammed Kozbar, since the days when hook-handed hate preacher Abu Hamza was imam from 1997 until 2003. May says police are treating the crash as a potential terrorist attack.
The incident came weeks after three Islamist radicals rammed a van into pedestrians on London Bridge before rampaging through Borough Market with knives, killing eight people before being shot dead by police.More news: Mexico Snatches Late 2-2 Draw against Portugal in FIFA Confederations Cup
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