Japan says it's continuing 'utmost efforts' to secure the release of a journalist from the country held by Islamic State.
It's now more than 24 hours since a message was released - seemingly featuring the voice of Kenji Goto.
In it, he said a Jordanian pilot also being held captive by IS would be killed - if Jordan didn't hand over an Iraqi prisoner.
Jordan has said it needs guarantees the pilot held by Islamic State militants is still alive before it can go ahead with a prisoner swap.
The jihadist group has demanded the release of failed suicide bomber Sajida al Rishawi in return for Jordanian pilot Lieutenant Muath al Kasaesbeh's freedom.
But a government spokesman in Amman said IS must provide proof that Mr al Kasaesbeh is not dead if it is to proceed with the deal.
Japanese Prime Minister Shinzo Abe said: "We are gathering and analyzing information while asking for cooperation from Jordan and other countries, making every effort to free Kenji Goto."
Officials initially agreed to a swap, but want proof the pilot's still alive.
Mr Goto's wife, Rinko, issued a statement saying she fears it is the "last chance" for her husband.
"I have not spoken out until now as I have been trying to protect my children and family from the media attention Kenji’s plight has created around the world," she said.
"I fear that this 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.
