Jordan has said it is ready to swap an Iraqi woman it is holding for a Jordanian pilot captured in December by extremists from the Islamic State group.
Information minister Mohammed al-Momani said "Jordan is ready to release the Iraqi prisoner" if the pilot, Lieutenant Mu'ath al-Kaseasbeh, is released unharmed, according to a statement on Jordan's state Petra news agency.
But Mr al-Momani made no mention of Japanese journalist Kenji Goto, who is also being held by IS.
It came after Mr Goto's mother made an emotional appeal to prime minister Shinzo Abe to save her son after his captors issued what they said was a final death threat.
Junko Ishido read out her plea to Mr Abe to "please save Kenji", which she said she sent today.
She begged Mr Abe to work with the Jordanian government to try to save Mr Goto, saying: "Kenji has only a little time left."
Mr Abe earlier expressed outrage, demanding that the extremists free her son, as secret talks sought the release of the two captives.
The efforts in Jordan to free Mr Goto and Lt al-Kaseasbeh gained urgency with the apparent ultimatum from IS yesterday.
In the message, the extremists said the hostages would be killed within 24 hours - tonight Japanese time - unless Jordan freed Sajida al-Rishawi, an Iraqi woman sentenced to death for her part in a 2005 terror attack on a hotel that killed 60 people.
"This was an extremely despicable act and we feel strong indignation. We strongly condemn that," Mr Abe said.
"While this is a tough situation, we remain unchanged in our stance of seeking help from the Jordanian government in securing the early release of Mr Goto."
In Jordan, the pilot's father, Safi al-Kaseasbeh, begged the government "to meet the demands" of the kidnappers.
"All people must know, from the head of the regime to everybody else, that the safety of Mu'ath means the stability of Jordan, and the death of Mu'ath means chaos in Jordan," he said.
About 200 of the pilot's relatives protested outside the prime minister's office in the Jordanian capital Amman, chanting anti-government slogans and urging that it meet the captors' demands.
Bassam al-Manasseer, chairman of the foreign affairs committee, said negotiations were taking place through religious and tribal leaders in Iraq, adding that Jordan and Japan would not negotiate directly with IS or free al-Rishawi in exchange for Mr Goto only.
A prisoner exchange would be contrary to the policy of Jordan's main ally, the US, which opposes negotiating with extremists.
Mr Goto's mother expressed hope for his release, but also desperation. "What has my child done wrong?" she said. "There's no more time."
The militants have reportedly beheaded one Japanese captive, Haruna Yukawa.
Yesterday's video resembled a message released over the weekend showing a still photo of Mr Goto holding what appeared to be a photo of Mr Yukawa's body. It withdrew a demand for 200 million dollars (£132 million) in ransom for Mr Goto and Mr Yukawa, made in an earlier message.
The videos, all of which lack the logo of IS's al-Furqan media arm, could not be verified independently, but some militant websites affiliated with IS referenced the latest video and posted links to it.
The latest message condemns Jordan for not releasing al-Rishawi, saying that unless she is freed within 24 hours, the pilot, followed by Mr Goto, will be killed. It says it is the group's last message.
"I have only 24 hours left to live and the pilot has even less," says the audio, purportedly from Mr Goto.
Lt al-Kaseasbeh, 26, has been held by the militants since his F-16 fighter jet crashed near IS's de facto capital of Raqqa, Syria, in December. He is the first foreign military pilot it has captured since a US-led coalition that includes Jordan began its aerial campaign against the extremists in August.