Islamic State (IS) militants in Syria have posted an online warning that a "countdown has begun" for the group to kill a pair of Japanese hostages.
The posting on January 23 shows a clock counting down to zero along with gruesome images of other hostages the group has beheaded.
IS militants on January 20 gave Japanese Prime Minister Shinzo Abe a 72-hour deadline to pay a $200 million ransom in exchange for the release of freelance journalist Kenji Goto and self-employed contractor Haruna Yukawa.
That deadline has already expired.
Japanese government spokesman Yoshihide Suga told reporters in Tokyo on January 23 that the government had not received any messages from the militants.
Hours earlier, Goto's mother made an emotional appeal on video for the kidnappers to release her son.
On January 20, the IS group released a video showing the two hostages while a man with a British accent threatened to execute them.