The Islamic State group (ISIS) has used Japanese hostage Kenji Goto to relay a new threat to kill a Jordanian pilot, unless Amman hands over an imprisoned female jihadist by sunset Thursday, monitoring group SITE Intelligence said.

The new threat came after Jordan offered Wednesday to exchange Sajida al-Rishawi, a would-be suicide bomber, for the pilot Maaz al-Kassasbeh, after the militant group’s earlier deadline for executing the airman and Goto was thought to have expired.

“I’m Kenji Goto Jogo. This is a voice message I’ve been told to send to you,” the Japanese journalist is heard to say in an unverified audio message distributed by ISIS-linked Twitter accounts.

“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 Mia’dh al-Jasaben (Maaz al-Kassasbeh) will be killed immediately,” Goto said according to a SITE transcript.

Japan has been seeking Jordan’s help in attempting to free Goto since an ISIS video released at the weekend said another Japanese hostage, Haruna Yukawa, had been beheaded.

After initially setting a $200 million ransom for Yukawa and Goto’s release, the Islamic State group, which rules swathes of Syria and  Iraq, changed tack and demanded Jordan free Rishawi.

Goto recorded a video of himself before he entered Syria late last October to report on the situation and locate Yukawa. In it, he identified himself and said “no matter what happens I will not bear a grudge against the Syrian people. No matter what happens, the responsibility is mine.”

AFP contributed to this report.