Japan is expending maximum efforts as it races against time to free two hostages the Islamic State group is threatening to kill within 72 hours, Prime Minister Shinzo Abe said Wednesday, vowing never to give in to terrorism. Abe returned to Tokyo from a Middle East tour ahead of schedule and convened a Cabinet meeting soon after. "It's a race against time, and we'll make an all-out effort and use every diplomatic route that we have developed to win the release of the two," he said. Abe said he was consulting with leaders in the region and had instructed officials to use all possible diplomatic channels to seek the hostages' release. The Islamic State group demanded a $200 million ransom in a video posted online Tuesday that showed a knife-brandishing masked militant standing over the two kneeling captives. Abe faces a hard choice: openly pay the extremists or ask an ally like the United States to attempt a risky rescue inside Syria. Japan's military operates only in a self-defense capacity at home. Abe and other government officials have not said directly whether or not Japan was considering paying the $200 million in ransom being demanded for the captives, Kenji Goto and Haruna Yukawa. Earlier, the government spokesman, Yoshihide Suga, confirmed that Japan believed the threat to be authentic. "Japan's aim is not to kill the Muslim people, as the militant group claims it to be," Suga said. "We strongly urge them not to harm the two Japanese and release them immediately."