Tory London mayoral candidate Boris Johnson was forced to defend his stance on Islam, insisting he believed it was a "religion of peace".
Mr Johnson has been criticised for an article he wrote in the wake of the 7/7 London terror attacks in 2005 claiming "Islam is the problem".
But Mr Johnson said the problem was extremists taking the words of the Koran out of context.
He said: "The problem is people who wrench out of context quotes from the holy book of Islam, the Koran, and use it to inspire evil in men's hearts.
"That is a fact that few serious people would deny and we need to tackle the extremists."
In a debate between the three main mayoral candidates on BBC One's Politics Show, Mr Johnson also raised concerns about uncontrolled immigration to the capital.
He said: "There has certainly been too much uncounted and unfunded immigration into London. That presents huge problems for the London Boroughs which have to cope with the influx."
The current Mayor, Labour's Ken Livingstone, said London could be a "model for the world" in terms of its ethnic diversity.
But he was forced to justify his decision to share a platform with the controversial preacher Yusuf al-Qaradawi. The cleric has described homosexuality as an "unnatural and evil practice" and said the Koran permitted wife-beating as "a possibility" in certain circumstances.
Mr Livingstone said: "He is a man who is prepared to say al Qaida is wrong and to be very strong in that condemnation."
