A man watches a news program, showing Japan's Prime Minister Shinzo Abe speaking at a news conference in Jerusalem, at an electronics store in Tokyo on Jan. 20, 2015. Abe on Tuesday condemned as "unacceptable" the threat to the lives of two Japanese purportedly taken captive by Islamic State militants, and said the international community should not give in to terrorism. Reuters/Toru Hanai

Update as of 4:17 a.m. EST: Japanese Prime Minister Shinzo Abe vowed to save the lives of two Japanese hostages held by the Islamic State group, stating that “their lives are the top priority.” Earlier on Tuesday, ISIS released a video threatening to kill Kenji Goto Jogo and Haruna Yukawa if the government failed to pay a ransom of $200 million in 72 hours.

“It is unforgivable and I feel strong resentment,” Abe said demanding the immediate release of the two hostages, according to The Associated Press.

Update as of 2:54 a.m. EST: Japanese Prime Minister Shinzo Abe said Tuesday that the country will not “give in to terrorism” and cancelled the rest of his trip in the Middle East, in response to the Islamic State group’s threat to kill two Japanese hostages, Agence France-Presse (AFP) reported.

The two hostages Kenji Goto Jogo and Haruna Yukawa have been identified as journalists associated with Japanese TV networks, according to AFP, while The Associated Press reported that Yukawa is a military contractor believed to have been abducted in Syria last August. A Reuters report from last August, which said Yukawa was captured in Syria that month, described him as a self-styled security consultant.

"If true, the act of threat in exchange of people's lives is unforgivable and we feel strong indignation," Japan’s Chief Cabinet Secretary Yoshihide Suga told AP. "We will make our utmost effort to win their release as soon as possible."

Update as of 2:30 a.m. EST: The Japanese foreign ministry's anti-terrorism unit has seen the video showing the Islamic State group threatening to kill two hostages, and analysts are assessing its authenticity, a ministry official told The Associated Press.

Prime Minister Shinzo Abe, who is in the Middle East on a six-day visit, is expected to appear at a news conference in Jerusalem later Tuesday. Kenji Goto Jogo, one of the two Japanese hostages, is reportedly a freelance journalist who went to Syria last year. Haruna Yukawa is a military contractor believed to have been abducted in Syria last August.

The Islamic State group released a video Tuesday threatening to kill two Japanese hostages if it was not paid $200 million, The Associated Press reported. ISIS has reportedly given authorities 72 hours to pay the ransom.

The video purports to show two hostages identified as Kenji Goto Jogo and Haruna Yukawa, AP reported, adding that the voice of the militant -- suspected to be a British national -- resembled the one involved in the beheading of several other hostages by the Sunni militant group. Yukawa, a Japanese private military contractor, is believed to have been kidnapped in Syria in August 2014, according to AP.

"You have proudly donated $100 million to kill our women and children, to destroy the homes of the Muslims," the militant says in the video, adding that the Japanese are being targeted for their country's support toward Western military efforts against ISIS. The militant, dressed in all black, also addresses Japanese nationals stating that they should pressurize their government to pay the ransom to save the lives of the two hostages.

A jihadi with a British accent had appeared in several videos last year showing the beheadings of several Western nationals. Last year, ISIS executed American hostages James Foley, Steven Sotloff and Peter Kassig, and British hostages David Haines and Alan Henning.

The Islamic State group is estimated to generate tens of millions of dollars each month through oil sales, ransom, extortion and other criminal activities, and from wealthy donors.