Prime Minister of Japan Shinzo Abe
Prime Minister of Japan Shinzo AbeFlash 90

Japanese Prime Minister Shinzo Abe has slammed as "utterly despicable" an Islamic State (ISIS) threat to kill a Japanese hostage within 24 hours unless Jordan releases a jihadi bomber.

"This was an utterly despicable act, and I am appalled," the Japanese prime minister told reporters Wednesday morning (local time), according to AFP.

"While we are in an extremely severe situation... the government is united to work for the early release of Mr. Kenji Goto,” he added.

"The government, in this extremely severe situation, has been asking for the Jordanian government's cooperation towards the early release of Goto, and this policy remains unchanged."

Abe urged ministers to do their utmost to resolve the issue and called on them to "take all possible measures to ensure the safety of Japanese nationals at home and abroad."

On Tuesday, ISIS threatened to kill Goto as well as captured Jordanian pilot Maaz al-Kassasbeh, if Jordan does not agree to release failed suicide bomber Sajida al-Rishawi.

Japan and Jordan are working together to try and secure the release of the two captives, after ISIS apparently beheaded Japanese contractor Haruna Yukawa last week after a 72-hour deadline for a $200 million ransom passed without payment.

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."