However, a spokeswoman for the coalition's Combined Joint Task Force said , externalshe was not aware of any operation, and the Pentagon's spokesman said there had been no raid involving US Special Operations troops.

Shortly afterwards, the Jordanian government is reported to have approached third parties, external from Turkey and Iraq and asked them to help negotiations for the release of Lt Kasasbeh. IS was said to have expressed interest in exchanging the pilot for imprisoned jihadists.

On 24 January, IS released a video purportedly showing the Japanese hostage Kenji Goto holding a picture of the decapitated body of another Japanese hostage, Haruna Yukawa, who he said was killed after Japan did not pay a $200m ransom.

Mr Goto said IS now sought a prisoner exchange. The group wanted Jordan's government to release Sajida al-Rishawi, an Iraqi woman who was sentenced to death for her role in a suicide bomb attack on a hotel in Amman in 2005 that killed 57 people, he added.

On 27 January, IS released another video with an audio track over a still picture that appeared to show Mr Goto holding a picture of Lt Kasasbeh. A voice believed to be that of Mr Goto said he had "only 24 hours left to live" and the pilot "even less" unless Rishawi was freed.

The following day, the Jordanian government said, external it was prepared to release Rishawi if Lt Kasasbeh was released unharmed.

No mention was made of Mr Goto, and on 31 January a video was published showing what appeared to be the body of the journalist.