Islamic State militants have threatened to kill two foreign hostages by Wednesday if demands for a prisoner exchange are not met, according to an online video message attributed to the group.
The statement on Tuesday repeated the request that Amman free Sajida al-Rishawi, a woman Jordanian authorities have held since she participated in a 2005 terror attack that killed 60 people in the capital.
The hostages, Japanese journalist Kenji Goto and Jordanian pilot Mu'ath al-Kaseasebeh, are believed to be in Islamic State custody.
Japan has requested help from Jordan to secure Goto's release.
A Japanese envoy in Jordan, Deputy Foreign Minister Yasuhide Nakayama, earlier expressed hope the two hostages would return home. Nakayama is overseeing efforts to secure Goto's release.
In a video released Tuesday featuring a photograph of Japanese hostage Kenji Goto, the speaker, whose voice resembles Goto's, said that he has “24 hours left to live.” The speaker on the video said the Jordanian pilot “has even less” time to live.
The authenticity of the video could not immediately be confirmed.
On Sunday Japanese Prime Minister Shinzo Abe called the apparent beheading of another Japanese captive, Haruna Yukawa, by the Islamic State group "outrageous and impermissible."
The Japanese leader told public broadcaster NHK that Japan will not give in to terrorism, and he called for the immediate release of Goto. Goto was captured while apparently trying to rescue Yukawa in Syria in October.
Saturday, the Islamic State posted a video online that showed Goto holding up photos appearing to show Yukawa's body, beheaded.
In that video, a man's voice directly addresses Abe, accusing him of responsibility for Yukawa's death.
The voice, purported to be Goto, said he would be freed in exchange for the release of al-Rishawi.
The Islamic State group, which controls a third of Syria and Iraq, threatened last week to behead the Japanese hostages within 72 hours unless it received a $200 million ransom.
Some material for this report came from Reuters and AP.