A prominent jihadi preacher has lashed out against Islamic State militants for burning to death a Jordanian pilot, saying this it was "not acceptable in any religion".

Abu Mohammed al-Maqdesi, considered a spiritual mentor for many al Qaida militants, spoke a day after being released from more than three months in detention in Jordan.

His release and harsh criticism of IS come at a time when the Jordanian government is trying to win broad popular backing for intensified air strikes against the militants in response to the killing of the pilot.

Earlier this week, IS militants released a video showing the pilot, Lieutenant Moaz al Kasasbeh, being burned to death in a cage.

In an interview with Jordanian TV station Roya, al-Maqdesi said that such an act "is not acceptable by any religion and by anyone".

The cleric indicated he had been involved in back-channel talks to arrange a possible prisoner swap to win the release of the pilot, who was captured after his plane crashed over Syria in December.

Jordan offered last week to swap an al Qaida prisoner for the pilot, but said after the release of the video that it became clear that the pilot had already been killed in early January.

Al-Maqdesi said the militants were never serious about arranging a swap.

"During my communication, they lied and they were evasive," he said. "They acted like they were interested (in a swap), but in fact they were not interested."

He also criticised IS for declaring a caliphate last year in the areas under its control in Syria and Iraq. Al-Maqdesi said a caliphate, or state run according to Islamic law, is meant to bring Muslims together, but that the militants have been a divisive force.

A decade ago, al-Maqdesi was considered a mentor of the al Qaida branch in Iraq, a precursor to the Islamic State group. However, the cleric fell out with his proteges over their methods, including attacks on fellow Muslims.

Jordan arrested the cleric in October after he criticised Jordan's participation in a US-led military coalition against IS. Jordan, which borders Syria and Iraq, joined the coalition in September.

In the wake of the killing of the pilot, Jordan said it would intensify its attacks. Dozens of fighter jets struck IS weapons depots and training areas yesterday, the military said.