'Sunset' Deadline Passes for ISIS Prisoner Swap

— -- The deadline for a prisoner swap that the terror group ISIS said would save the life of a Jordanian hostage has passed, apparently with no news of the swap taking place.

Through a message from Japanese hostage Kenji Goto, ISIS had demanded the government of Jordan release al Qaeda convict Sajida al-Rishawi and bring her to the border with Turkey by "sunset" Mosul time, meaning mid-morning East Coast time, in exchange for Goto's freedom. If Jordan refused, ISIS said it would kill a captured Jordanian pilot, Lt. Muath al-Kaseasbeh.

But just before the sun set in Mosul, a spokesperson for the Jordanian government said ISIS had yet to provide proof that al-Kaseasbeh was still alive.

Jordan’s government has said it would go through with a prisoner swap in order to get its captured pilot back, but Goto's message did not say the Jordanian pilot would be freed in the newly-proposed arrangement. Al-Kaseasbeh was captured by ISIS last December after his aircraft was shot down.

"We want to see proof of life of the Jordanian pilot and then we can talk about the exchange between Sajida [al-]Rishawi and the Jordanian pilot," al-Momani said.

Al-Rishawi, the Iraqi woman ISIS is bent on freeing, has been on death row in Jordan since she confessed to her role as a would-be suicide bomber in a string of al Qaeda attacks in Jordan in 2005 that killed dozens.

Kenji Goto's wife, Rinko, released a statement this morning, saying she has been in contact with those holding her husband for weeks, and last received a message from them demanding that she publicize the proposed exchange with the Jordanian government.

"I fear that his is the last chance for my husband and we now have only a few hours left to secure his release and the life of Lt. Muath al-Kaseasbeh. I beg the Jordanian and Japanese Government to understand the fates of both men are in their hands," she said. "I pray for the lives of my husband and the Jordanian pilot Lt. Muath al-Kaseasbeh."

Junko Ishido, Goto's mother, said after the passing of the deadline that she was "disappointed."

“But I just can’t feel helpless,” Ishido said, according to the Japanese news agency NHK. “We have to think how the captors will follow through [with] their promise to release my son. We can’t just give up hope.”

Prior to reports of Jordan’s willingness to accept the trade, Middle East expert Jon Alterman told ABC News that by asking for, and potentially gaining al-Rishawi’s release, ISIS is attempting to bolster its long-held goal of being seen as a proper nation-state on a geopolitical scale.

“What it represents is ISIS again trying to act like a real country. It’s a small group of outlaws trying to engage in governments,” Alterman, head of the Middle East Program at the Center for Strategic and International Studies, said Tuesday.

ISIS, the Islamic State of Iraq and Syria, has publicly beheaded dozens of captives, including a handful of Western journalists and aid workers, sometimes after making demands of their governments.

ABC News' Nadine Shubailat contributed to this report.