Relatives of Islamic State captive Jordanian pilot al-Kasaesbeh hold his poster as they take part in a rally in his support at the family's headquarters in the city of Karak. Reuters

AFP

Jordan vowed Sunday to do all it could to save an airman held by the Islamic State group after the jihadists killed a Japanese journalist they had been holding.

The kingdom "will do everything it can to save the life and secure the release of its pilot," Maaz al-Kassasbeh, who was captured by the jihadists after his plane crashed in Syria in December, government spokesman Mohammed al-Momeni told the official Petra news agency.

IS has been demanding the release of a convicted Iraqi jihadist on death row in Jordan in exchange for Kassasbeh's life, a demand the government has expressed readiness to accept provided it is given proof he is still alive.

"All state organisations have been mobilised to secure the proof of life that we require so that he can be freed and returned to his home," Momeni said.

He condemned the jihadists' murder of Japanese journalist Kenji Goto after days of intensive efforts through intermediaries to save him.

"We spared no effort, in coordination with the Japanese government, to save his life," Momeni said.

Goto was the second Japanese hostage in a week to be executed by the jihadists in what they have said is punishment for Tokyo's pledge of $200 million (175 million euro) in aid to countries affected by its bloody seizure of swathes of Iraq and Syria last year.

Last week, IS claimed responsibility for the beheading of Haruna Yukawa after the expiry of a 72-hour ultimatum.

The jihadist IS wants freed -- Sajida al-Rishawi -- was sentenced to death for her role in the 2005 bombings of three Amman hotels by Al-Qaeda in Iraq which killed 60 people.

Her husband was one of the three suicide bombers and the court found that she had would have been a fourth but for the failure of her detonator.