Tokyo: Japanese Prime Minister Shinzo Abe said on Monday he wanted to debate the possibility of Japan's military rescuing Japanese citizens abroad, a day after Islamic State militants said they had beheaded a Japanese journalist.

The militants said on Sunday they had beheaded Kenji Goto, a veteran war reporter, after international efforts to secure his release through a prisoner swap failed. They killed another Japanese hostage, Haruna Yukawa, a week before.

Abe reiterated his denunciation of the militants and said Japan was firmly committed to fulfilling its responsibility as a member of the global community in fighting terrorism and that it needed to be able to protect its citizens.

"Preserving the safety of Japanese nationals is the responsibility of the government, and I am the person who holds the most responsibility", Abe told a parliamentary committee, adding that he wanted to discuss a framework for rescuing Japanese in danger.

Scope for the military to mount rescue missions is limited by law but the government already plans to submit revisions to parliament to ease restrictions.

Even some advocates of changes to make rescues possible, however, say Japan's military faces difficulty in acquiring the capacity to conduct such missions. Critics say sending troops overseas would just increase the risk.

Abe's government had put high priority on saving Goto, who was captured when he went to Syria to try to seek Yukawa's release.

An opinion poll by Kyodo news agency on 25 January, just after Yukawa was killed, found 61 percent of respondents supportive of the government's response.