Tony Blair has said religion needs to be put "in its proper place in politics" in order to defeat terrorists who "fight without hesitation, kill without mercy and die without regret".
Speaking from outside the United Nations' headquarters in New York, the former prime minister and current peace envoy to the Middle East said Islamist ideology had created an enemy that was "insidious and venomous, but also difficult to beat".
And he called for the "basic long-term problem of extremism based on a perversion of religion" to be confronted following the Westgate mall massacre in Kenya, deadly attacks on Christians in Pakistan and the conflagrations in the Middle East.
He told Sky News: "We need to realise that unless we are educating people to a tolerant and respectful and open-minded approach to the world, then this cancer of terrorist groups will continue.
"The thing about these people is that they fight without hesitation, they kill without mercy and they die without regret."
Asked if he had hoped for an end to al Qaida after the death of Osama Bin Laden, he said: "No because it doesn't put an end to the ideology.
"I think it's right that it happened and it will have had a certain impact and it shows that if you organise these terrorist attacks in the end the long arm of the law will ultimately come out and get you.
"But this is a vibrant ideology that stretches quite deep, I'm afraid, in certain countries.
"If you look at the Middle East right now, if you took out this toxic abuse of religion, all these situations would be easier to deal with.
"One of the things I work on now and I am very passionate about is the need to put religion in its proper place in politics and also to encourage people who are religious to be tolerant and respectful of those who have a different faith from theirs.
"This is deep and this ideology is being pushed out from the Middle East but elsewhere now, right across the world, and we are a long way from beating it I'm afraid."
Mr Blair was speaking after it was announced that Britain, the US, Russia, France and China may be edging closer to a United Nations Security Council resolution designed to rid Syria of its chemical weapons.
He welcomed the possibility of an agreement on chemical weapons without the need for military intervention, but warned that a "threat of firm action from the West" to bring the fighting in Syria to an end would still be needed.
"Unless we do that Syria, will continue disintegrating and the implications for the region are huge and the implications for us are huge as well by the way," he said.
The was a risk that the country could be effectively partitioned with President Bashar Assad and minority groups on one side and an "extremist-dominated eastern hinterland".
"That would be a disaster for everyone," he said.
Finally asked about revelations that Gordon Brown's former spin doctor Damian McBride had briefed against members of his own party, Mr Blair declined to comment.
"Here in the United Nations it all seems a long, long time ago and a long way away," he said.