A recent photo showing journalist Jumpei Yasuda pleading for his last chance to live is not an empty threat, according to a Syrian liaison between the media and the people holding him hostage, who have reportedly set a one-month deadline.

"They want $10 million in exchange and if they don't get it they're going to trade him to ISIS to get back their own people," Syrian journalist Tarik Abdul Hak, who has been involved in the negotiations, told The Japan Times through an interpreter Monday.

ISIS is one of the acronyms used to refer to the Islamic State militant group.