In a new video purportedly released by ISIS, a masked militant threatens to behead two Japanese hostages—identified in the clip as Kenji Goto and Haruna Yukawa—within 72 hours if Japan does not pay a $200 million ransom.

The alleged ISIS agent in the video, clad in black and pointing a knife at the men seen kneeling in a barren landscape, claims the threat is in retaliation for Japan's recent pledge to provide non-military assistance to countries fighting the Islamic State. The video has yet to be independently verified.

"To the Japanese public, just as how your government has made the foolish decision to pay 200 million to fight the Islamic State, you now have 72 hours to pressure your government in making a wise decision by paying the 200 million to save the lives of your citizens," the masked man said in the video says. "Otherwise this knife will become your nightmare."

According to the BBC, Goto is a freelance journalist; Yukawa reportedly traveled to Syria to set up a private military contracting company.

"Using human lives as a shield to make threats is an unforgivable terrorist act, and I am extremely indignant," Japanese Prime Minister Shinzo Abe at a news conference in Jerusalem Tuesday. "I strongly demand that they be released unharmed immediately."

Should the video prove to be true, the men would join James Foley, Steven Sotloff, David Cawthorne Haines, Alan Henning as known ISIS hostages, all of whom were beheaded.