Brutal murders carried out by Islamic State could be "the best thing that ever happened to the world", televangelist Pat Robertson has claimed.

The controversial right-wing pastor made the comments on his TV programme 'The 700 Club' while promoting his latest book on Islam. Robertson suggested that Islamic State militants were exposing the true Islam by engaging in such atrocities.

"You wonder. Maybe the best thing that ever happened to the world is for these crazies in ISIS to keep on beheading people and doing some of these extreme things," he said.

"Listen, you've heard all this business about Islam being a religion of peace. Islam does not mean 'peace', it means 'submission'."

It is not the first time that Robertson has courted controversy. Last month he was widely condemned for his response to a woman asking what she should say to a colleague whose young child had died.

"As far as God's concerned, he knows the end from the beginning and he sees a little baby and that little baby could grow up to be Adolf Hitler, he could grow up to be Joseph Stalin, he could grow up to be some serial killer, or he could grow up to die of a hideous disease," Robertson said.

"God sees all of that, and for that life to be terminated while he's a baby, he's going to be with God forever in Heaven so it isn't a bad thing."

Speaking earlier this week, US President Obama insisted that the fight against Islamic State is not against Islam.

"In order for us to defeat terrorist groups like ISIL and al-Qaeda, we must discredit their ideology," he said at the Pentagon on Monday.

"Ideologies are not defeated with guns, they are defeated by better ideas. We will never be at war with Islam."