A voice recording, purportedly by the Islamic State, says a Jordanian pilot held by the group will be executed, if an Iraqi prisoner held by Jordan is not released by sunset on Thursday.
The militant group had demanded the release of failed suicide bomber Sajida al-Rishawi in exchange for their Japanese hostage Kenji Goto, but Jordan said it would only free Ms Rishawi if Jordanian air force pilot Moaz al-Kasasbeh is also released.
The latest voice clip, which is currently being investigated by Japan, appears to have Mr Goto conveying Islamic State's rejection of the counter offer and demands Ms Rishawi's release.
"I am Kenji Goto. This is a voice message I've been told to send to you. If Sajida al-Rishawi is not ready for exchange for my life at the Turkish border by Thursday sunset 29th of January Mosul time, the Jordanian pilot Moaz al-Kasasbeh will be killed immediately," the unverified recording says.
IS already executed one Japanese hostage and threatened to do the same to MR Goto if Ms Rishawi isn't released.
Japan condemns 'hostage execution' (24 Jan 2015)