ISIS may have already beheaded one of the Japanese hostages being held by the organization, according to a video uploaded to the terror organization's Twitter account Saturday.
In the video, Kenji Goto appears to be holding a gruesome photo showing the beheaded body of fellow hostage Haruna Yukawa.
Goto blames Japanese Prime Minister Shinzo Abe for Yukawa's death - and explains that he, too, will be executed unless Jordan releases terrorist Sajedah Rishawi. The $200 million ransom fee claimed in earlier videos has apparently been waived.
Goto then turns to his wife and tells her of his longing for her and his two daughters, begging Abe "not to kill" him, too. He explains that it is possible to prevent his murder by working with Jordanian officials in his home country.
Earlier Saturday, Japan's attaché in Jordan stated that it would "never give up" its search for both hostages.
"It is a very difficult path to see their release, despite a variety of routes," Deputy Foreign Minister Yasuhide Nakayama stated to AFP from Amman. "We are focusing on scrutinizing information over again. We will never give up. We will bring them home."
Foreign Minister Fumio Kishida told reporters there was "nothing new to report" after holding a meeting of an emergency task force on Saturday morning.
Junko Ishido, Goto's mother, on Friday launched an emotional appeal begging for mercy for her son.
"I say to you people of the Islamic State, Kenji is not your enemy. Please release him," she said.
Japanese officials said they are still trying to secure a channel of communication to contact the Islamic State group as they scrutinize various information.
Yosuke Isozaki, an advisor to Prime Minister Shinzo Abe, on Friday reportedly said there had been some "indirect" communication with the
terrorists, but "nothing direct."
Tokyo has little diplomatic leverage in the Middle East, but local media say Abe may try to use his close relationship with Turkey's President Recep Tayyip Erdogan to rescue the hostage.
Japan's Yomiuri Shimbun newspaper reported Saturday that Jordan has also tried to contact the Islamic State through influential religious leaders in Amman.
Later on Friday, US ambassador to Japan Caroline Kennedy and US military officials visited Japan's defence chief Gen Nakatani at the ministry.
"The US government is ready to offer any assistance and support that we can to Japan because we are such strong partners," she said.
The Japanese media has rallied around Goto, a respected and experienced war reporter whose work has appeared on domestic television channels.
In video footage he filmed around the time he entered Syria, he holds identification papers and his Japanese passport and explains that he is aware of the risks.
"Whatever happens, I am the one who is responsible," he says. "I am asking you, Japanese people, do not place responsibility on the people of Syria. Please. I am sure I will come back alive though."