"Hatred and evil of this kind will never succeed", she said.
London Mayor Sadiq Khan, the first Muslim to serve in that position, urged residents to focus on their shared values and to stand together during this an unprecedented period in the capital's history.
Sky News reported that the mosque's imam prevented the crowd from beating the attacker until police arrived.
Khan told Sky News that Mahmoud's actions "calming things down" were "what I'd expect from a good faith leader, from a good Muslim leader".
(CNN) As the United Kingdom and the world process what happened in London's Finsbury Park, it's important we learn the right lessons.
Algeria on Monday strongly condemned the "hateful" terrorist attack that targeted Muslims near Finsbury Park mosque in northern London in Britain.
Counter-terror officials said they were closely monitoring terror activity linked to far-right groups but most of the recent attacks have been traced to individuals rather than groups. But those who want to engage in a cultural war against Muslims and Islam are far more numerous. Police believe the rampage is inspired by extremist ideology. Early police caution about declaring the incident to be terrorist-related was interpreted by the community as discriminatory.
After being seized, he said he had wanted to kill "many Muslim people", one witness told journalists.
One elderly man, who had collapsed moments before the van appeared, was pronounced dead at the scene, although police have not yet confirmed whether he died as a result of the attack. Parents are scared to send their children to evening prayers.
Finsbury Park Mosque said it was a "callous terrorist attack" and noted it had occurred nearly exactly a year after a man obsessed with Nazis and extreme right-wing ideology murdered lawmaker Jo Cox, a former humanitarian aid worker. Add to that the trauma from the Manchester attacks, it is not possible for people not to panic.
The mosque itself gained notoriety more than a decade ago for sermons by radical cleric Abu Hamza al-Masri, who was sentenced to life in a USA prison in January 2015 after being convicted of terrorism-related charges.
His mother Christine, 72, said she was living "every mother's worst nightmare" and screamed when she saw her son on TV.
It will assign more police in the London area. She said her thoughts were with the injured, their loved ones and emergency officials who responded to the incident. She has also been criticized for her response to a fire in a London tower block last Wednesday which killed at least 79 people.