TOKYO (AP) — Japan said it was putting its trust in Jordan to help gain the release of a Japanese journalist held by Islamic State militants, after the latest message purportedly from his captors extended until sundown Thursday in the Middle East the deadline for the Jordanians to release an Iraqi prisoner.

The message, read in English by a voice the Japanese government said was likely that of hostage Kenji Goto, was released online late Wednesday after Jordan offered to hand over the al-Qaida-linked would-be suicide bomber to the Islamic State group in exchange for Jordanian air force pilot Lt. Muath al-Kaseasbeh.

The recording says Jordan must present Sajida al-Rishawi, an Iraqi woman convicted of involvement in deadly Amman hotel bombings in 2005, at the Turkish border by sunset Thursday, in exchange for Goto's life or the pilot would be killed. It wasn't clear what Goto's fate would be if the woman wasn't returned.

The message clearly stated the deadline was sundown in Mosul, Iraq, the largest city held by the militant group.

The Associated Press could not independently verify the contents of the recording, which was distributed on Twitter by Islamic State-affiliated accounts.

In Tokyo, government spokesman Yoshihide Suga said Thursday the government was in close communications with the Jordan government. He said Japan was doing its utmost to free Goto, working with nations in the region, including Turkey, Jordan and Israel.

"As the situation is developing, I shouldn't comment on details. But, Japan and Jordan are dealing with the matter based on an extremely trusting relationship," Suga told reporters.

Efforts to free al-Kaseasbeh and Goto gained urgency after a purported online ultimatum claimed Tuesday that the Islamic State group would kill both hostages within 24 hours if Jordan did not free al-Rishawi.

Japan has scrambled to deal with the crisis that began last week with the release of a video by the Islamic State group showing Goto and another Japanese hostage, Haruna Yukawa, kneeling in orange jumpsuits between a masked man who threatened to kill them within 72 hours unless Japan paid a $200 million ransom.

That demand has since shifted to one for the release of al-Rishawi. The militants have reportedly have killed Yukawa, 42, although that has not been confirmed.

"This heinous terrorist act is totally unforgivable," Prime Minister Shinzo Abe said in parliament Thursday.

Goto, a freelance journalist, was captured in October in Syria, apparently while trying to rescue Yukawa, who was taken hostage last summer.

In Tokyo, Goto's mother, Junko Ishido, has been desperately pleading for the government to save her son.

"I know Mr. Abe is someone who can handle this matter. I trust Mr. Abe and I can do nothing but rely on him," she said.

In his announcement that Jordan is ready to trade al-Rishawi for the pilot, government spokesman Mohammed al-Momani made no mention of Goto.

Releasing the would-be hotel bomber linked to al-Qaida would breach Jordan's usual hard-line approach to the extremists and set a precedent for negotiating with them.

It would also be a coup for the Islamic State group, which has already overrun large parts of neighboring Syria and Iraq. Jordan is part of a U.S.-led military alliance that has carried out airstrikes against the extremist group in Syria and Iraq in recent months.

The Islamic State group has not publicly demanded prisoner releases before and Jordan's main ally, the United States, opposes negotiations with extremists.

Jordanian King Abdullah II faces growing domestic pressure to bring the pilot home. The pilot's father said he met on Wednesday with Jordan's king, who he said assured him that "everything will be fine."

The pilot's capture has hardened popular opposition among Jordanians to the air strikes, analysts said

"Public opinion in Jordan is putting huge pressure on the government to negotiate with the Islamic State group," said Marwan Shehadeh, a scholar with ties to ultra-conservative Islamic groups in Jordan. "If the government doesn't make a serious effort to release him, the morale of the entire military will deteriorate and the public will lose trust in the political regime."

Jordan reportedly is holding indirect talks with the militants through religious and tribal leaders in Iraq to secure the release of the hostages. In his brief statement, al-Momani only said Jordan is willing to swap al-Rishawi for the pilot. He did not say if such an exchange is being arranged.

The 26-year-old pilot, al-Kaseasbeh, was seized after his Jordanian F-16 crashed in December near the Islamic State group's de facto capital of Raqqa in Syria. He is the first foreign military pilot the militants have captured since the coalition began its airstrikes in August.

Previous captives may have been freed in exchange for ransom, although the governments involved have refused to confirm any payments were made.

The Islamic State group broke with al-Qaida's central leadership in 2013 and has clashed with its Syrian branch, but it reveres the global terror network's former Iraqi affiliate, which battled U.S. forces and claimed the 2005 Amman attack.

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Laub reported from Amman, Jordan. Mohammed Daraghmeh in Ramallah, Omar Akour in Amman, Jordan, and Kaori Hitomi, Mari Yamaguchi, Emily Wang and Koji Ueda in Tokyo contributed to this report.

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Follow Karin Laub on Twitter at www.twittter.com/karin_laub. Follow Elaine Kurtenbach at www.twitter.com/ekurtenbach.