Japan promised not to give up "until the very end" on efforts to rescue two Japanese hostages threatened with beheading by Islamic militants, after a deadline passed with no word from the captors.
Militants affiliated with the Islamic State (IS) group posted an online warning yesterday that the "countdown has begun" for the extremists to kill 47-year-old Kenji Goto and 42-year-old Haruna Yukawa.
The extremists had given Japanese prime minister Shinzo Abe 72 hours to pay the 200 million US dollar (£133 million) ransom, and the deadline expired yesterday.
The posting, which appeared on a forum popular among IS militants and sympathisers, did not show any images of the hostages, who are believed to be held somewhere in Syria.
Yasuhide Nakayama, a deputy foreign minister sent to Amman, Jordan, said he was working around the clock to co-ordinate efforts to save the hostages.
"We will not rule out any possibility, and we are verifying all information thoroughly," he said.
"We will not give up until the very end to rescue the two so we can go home together."
Yet, the fate of the two men remained unclear today.
Senior government spokesman Yoshihide Suga was asked about yesterday's message and said Japan was analysing it.
"The situation remains severe, but we are doing everything we can to win the release of the two Japanese hostages," he said.
Japan is using every channel it can find, including local tribal chiefs, to try to reach the captors, he added.
He said there has been no direct contact with the captors.
Mr Abe yesterday discussed the crisis with his national security council.
Japan has scrambled for a way to secure the release of Mr Goto, a journalist, and Mr Yukawa, an adventurer fascinated by war.
Its diplomats left Syria as the civil war there escalated, adding to the difficulty of contacting the militants holding the hostages.
Worshippers at Tokyo's largest mosque yesterday offered prayers for the two hostages.
"All Muslims in Japan, we want the Japanese hostages to be saved as soon as possible," said Sandar Basara, a worker from Turkey.
Mr Goto's mother made an appeal for his rescue.
"Time is running out. Please, Japanese government, save my son's life," said Junko Ishido. "My son is not an enemy of the Islamic State."
She s aid she was astonished and angered to learn from her daughter-in-law that Mr Goto had left for Syria less than two weeks after his child was born in October to try to rescue Mr Yukawa.
Japanese officials have not directly said whether they are considering paying any ransom. Japan has joined other major industrial nations in the Group of Seven in opposing ransom payments. US and British officials said they advised against paying.