Japan's Prime Minister Shinzo Abe speaks to the media at his official residence in Tokyo in this photo by Kyodo. Abe expressed anger early Sunday, local time, at a video purporting to show the execution of a Japanese citizen by Islamic State militants and insisted Tokyo will not bow to terrorism. Reuters

U.S. President Barack Obama and other world leaders Saturday condemned a video allegedly from the Islamic State Group announcing the beheading of one of its two Japanese hostages. Obama, Japanese Prime Minister Shinzo Abe and British Prime Minister David Cameron each issued strong statements denouncing the video, which has yet to be authenticated.

The militant organization, often called ISIS or ISIL, posted a video purporting to show Japanese war correspondent Kenji Goto holding a photo of the body of contractor Haruna Yukawa. Japan had previously refused to pay a $200 million ransom for the men’s release. Now, Goto said in the video, ISIS wanted the release of suicide bomber Sajida al-Rishawi, who is in Jordanian custody.

Abe told reporters the acts were “outrageous and unforgivable,” the Associated Press reported. The video and alleged beheading sparked reactions from several foreign officials who govern countries previously threatened by ISIS.

Obama addressed "the brutal murder of Japanese citizen Haruna Yukawa by the terrorist group ISIL” and extended condolences to Japan. Last fall, ISIS fighters killed American journalists James Foley and Steven Sotloff as well as aid worker Peter Kassig.

In a statement Saturday, Obama demanded the immediate release of Goto and all other hostages. “We stand shoulder to shoulder with our ally Japan and applaud its commitment to peace and development in a region far from its shores,” he said. “We will work together to bring the perpetrators of these murders to justice and will continue to take decisive action to degrade and ultimately defeat ISIL.​”

Cameron also damned ISIS’s latest actions, which he referred to as “another reminder of the murderous barbarity of these terrorists,” ITV reported. ISIS members beheaded British humanitarian aid worker Alan Henning in October. Cameron said Saturday England “stands in solidarity with the Japanese people” and supports Abe’s reaction to the incidents. Both the U.S. and U.K. had advised Japan against paying ransom for the men.