The fate of Kenji Goto and Haruna Yukawa – the two hostages held by Islamic State (Isis) – remains unknown, after the deadline for paying a $200m (£133.4m) ransom expired.
The Islamist organisation has not made any announcement after the deadline ended Friday afternoon local time.
Japanese officials continue their efforts in seeking a safe release of the captives.
Yasuhide Nakayama, the senior Japanese diplomat who is overseeing the operation, told reporters that the Japanese government remains "focused on gathering information and combing through it. We in the government will pull through this together and put priority on saving human lives".
The Japanese delegation has set up a task force in Amman, Jordan, as they coordinate with Jordan and Turkey over the incident. Islamic State demanded $200m in exchange for the release of journalist Kenji Goto, 47, and private security contractor Haruna Yukawa, 42.
Officials in Tokyo insist no contact has been made with the kidnappers.
"We haven't received any particular [message]. This situation is still difficult, but we'll do our utmost to ensure the release of the hostages," Chief Cabinet Secretary Yoshihide Suga told reporters in Tokyo.
Local reports suggest that the captives' families have been informed by Japanese authorities that no ransom will be paid, as it would tantamount to funding the extremist group and further encourage them in such extortion bids.
There are unverified claims in social media that the two hostages have been executed and a video of their beheadings is being produced.