01/24/2015 11:01 am ET Updated Dec 06, 2017

Alleged ISIS Video Claims Japanese Hostage Haruna Yukawa Was Executed, Issues New Demand

Members of the Islamic State militant group circulated an online video on Saturday claiming they have executed Japanese hostage Haruna Yukawa.

A still image of the second Japanese man held by the group, Kenji Goto Jogo, appears in the video holding a picture purportedly of Yukawa's body. In audio, a man purporting to be Goto pleads for his life and says the militant group is now demanding a prisoner exchange for a suspected female militant imprisoned in Jordan, Sajida al-Rishawi.

The Japanese government is trying to verify the video, Japanese state TV said, and convened an emergency cabinet meeting. Prime Minister Shinzo Abe called the release of the new message "an outrageous and unforgivable act," and demanded the hostages' release. "We will not give in to terrorism," he vowed.

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Japanese Prime Minister Shinzo Abe speaks to reporters after a cabinet meeting at his official residence in Tokyo on Jan. 25, 2015. (YOSHIKAZU TSUNO/AFP/Getty Images)

The format of the video differed from earlier releases by the group, raising skepticism among some analysts over its authenticity.

U.S. intelligence officials are also working to confirm whether the video is authentic, Patrick Ventrell, a spokesman for the White House National Security Council, told the Associated Press.

Japan's Kyodo News agency said the video had also been emailed to the wife of one of the hostages, the Associated Press reported.

The Islamic State had first threatened the lives of the two hostages in a video released on Tuesday. That clip showed both men kneeling in a desert landscape as a masked militant ordered the Japanese government to pay $200 million in ransom money within 72 hours, in exchange for the hostages' release.

"To the prime minister of Japan: Although you are more than 8,500 kilometers away from the Islamic State, you willingly have volunteered to take part in this crusade," the militant said in the video released Tuesday.

Goto, a Tokyo-based freelance journalist, launched his own video news company in 1996 and is mostly known for his work on humanitarian disasters in war zones. He traveled to Syria in 2014 to report on the country's civil war and was abducted in the fall.

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Junko Ishidou, the mother of Kenji Goto, speaks at a press conference on Jan. 23, 2015 at the foreign correspondents club of Japan in Tokyo. (David Mareuil/Anadolu Agency/Getty Images)

The Associated Press reports that Yukawa, the founder of a private security company, was kidnapped in August 2014. He was in Syria to train with militants, and documented his stay in blog posts and on his Facebook page.

The Islamic State has killed several hostages from Western countries in recent months, and has announced their deaths in online videos. The militant group has claimed responsibility for the killings of American journalists James Foley and Steven Sotloff, American aid worker Abdul-Rahman Kassig and Britons Alan Henning and David Haines. U.S. President Barack Obama on Saturday strongly condemned the apparent killing of Yukawa.

A wave of kidnappings by extremist groups like al Qaeda and the Islamic State in Syria and Iraq has forced governments around the world to take a position on whether or not to pay ransom for hostages. Several European nations are believed to have paid millions in recent years to secure the release of kidnapped citizens. The U.K. and the U.S. maintain no-ransom policies.

Speaking after the first video, Abe called the kidnappings "unacceptable" and called on the militants to release the captives. Asked whether the Japanese government would pay the ransom, Abe said his administration "attaches the utmost priority to saving lives."

After the new clip emerged on Saturday, the Japanese prime minister said: "We are using every diplomatic channel and means to work towards a release."