Jordan said on Wednesday that it was willing to carry out the swap, which the "Islamic State" (IS) group had demanded in exchange for the release of a Japanese journalist and a Jordanian pilot.

"Jordan is ready to release the Iraqi prisoner, Sajida al-Rishawi, if the Jordanian pilot, Muath al-Kaseasbeh, is freed unharmed," the official Petra news agency reported.

The announcement did not mention Japanese journalist Kenji Goto, who is also being held by the group. A video released on Wednesday, apparently showing images of Goto a day earlier, said he would be killed unless al-Rishawi was released.

But the voice also said al-Kaseasbeh had a shorter time to live. The pilot was captured by the IS on December 24 after his fighter jet crashed during a mission against the militant group in northern Syria.

Al-Rishawi was sentenced to death in Jordan for her involvement in a 2005 terrorist attack by al Qaeda, targeting hotels in Amman. Sixty people were killed. She is the sister of Samir Atruss al-Rishawi, a late top lieutenant of Jordanian-born Abu Musab al-Zarqawi, the al Qaeda leader in Iraq who was killed in 2006.

The Japanese government believed the IS deadline would expire at around 1400 GMT on Wednesday. It has sent Deputy Foreign Minister Yasuhide Nakayama to Amman to coordinate efforts with Jordan.

The militants have reportedly already beheaded one Japanese hostage, Haruna Yukawa.

Japanese Prime Minister Shinzo Abe told a Cabinet meeting on Wednesday that he was "appalled" by the events.

"This was an utterly despicable act, and I am appalled," Abe told reporters. "While we are in an extremely severe situation ... I have instructed all ministers to work together for the early release of Mr. Kenji Goto."

Goto's mother has made a last-ditch appeal for her son's life. "Kenji has only a little time left," Junko Ishido said.

The Islamic State, which currently controls large areas in Iraq and Syria, has murdered five Western hostages since August.

jr/sms (AP, AFP)