Japanese Government 'considered whether hostage threat was basis for military strike' against Isis

Document reveals capture was deemed ‘unacceptable act of terror’ but did not meet conditions for dispatching troops

Junko Ishido, mother of Kenji Goto, a Japanese journalist being held captive by Islamic State militants along with another Japanese citizen, reacts during a news conference at the Foreign Correspondents' Club (Reuters)

The Japanese Government considered whether the capture of two hostages and threat to their lives amounted to legal basis for a military strike against Isis as it scrambled for ways to free the men, a document seen by Reuters has revealed.

The capture of Kenji Goto and Haruna Yukawa was deemed an "unacceptable act of terror," according to the briefing document compiled by Japanese officials before the 72-hour deadline expired.

However, the Government found the situation did not meet the conditions for the dispatch of Japanese forces.

Japan's pacifist constitution bans its troops fighting overseas, among other restrictions on the military.

The coalition government approved a controversial reinterpretation of the constitution in July to allow forces to fight overseas in order to engage in self-defence and come to the aid of a military ally under attack for the first time since the Second World War.

Officials have been searching for a solution to save the lives of Mr Goto and Mr Yukawa after Isis released a video showing them being held hostage on Tuesday.

A militant in the video demanded a $200 million ransom for both men within 72 hours, a deadline that is believed to have expired at 5.50am GMT today.

Mr Goto's mother made an emotional plea for help in saving the life of her son in a tearful speech on Friday.

Junko Ishido, mother of Kenji Goto (Reuters)

There has been no news from Isis on the condition of the men at present.