Islamic State extremists have confirmed they executed a Japanese man they had been holding hostage.

A spokesman for the group said security contractor Haruna Yukawa (42) was killed after the deadline for his ransom expired. The announcement was made on Al-Bayan radio, which broadcasts in areas under IS control in Iraq and Syria.

Mr Yukawa was one of two Japanese men Islamic State militants had taken captive.

The Japanese government has condemned the apparent killing. Prime Minister Shinzo Abe slammed "an outrageous and unforgivable act" after a video reportedly showing an image of captive Kenji Goto holding a picture of a beheaded Haruna Yukawa was posted online.

The clip also purportedly contained the voice of journalist Mr Goto (47) claiming the private military company operator had been killed.

Mr Abe said the video, which also includes a demand for a prisoner exchange for Mr Goto, appears to be authentic.

Kyodo News agency reported the same video had been emailed to the wife of one of the hostages.

The jihadist group Islamic State (IS) had threatened to kill the captives unless a US$200m (€178.4m) ransom was paid to secure their release.

The 72-hour deadline set by the Islamist militants expired on Friday.

Mr Yukawa's father said he hoped "deep in his heart" that the news of his son's killing was not true.

Mr Abe insisted Tokyo would not bow to terrorism and said his government would spare no effort to secure the release of the remaining captive.

But he reiterated that Japan would not give in to terrorism.

Video

In the video, Mr Goto apparently said IS was no longer demanding money for his release and now wanted a female alleged suicide bomber freed from detention in Jordan.

He spoke in English, blaming Mr Abe for Mr Yukawa's death, and told his wife and family not to give up on him.

The hostages had appeared in videos wearing the same orange jumpsuits as those worn by captives in previous IS videos. The mother of Mr Goto has pleaded with militants to spare her son's life.

Junko Ishido said he is a friend of Islam who devoted his life to helping children in war zones.

Mr Yukawa was seized by militants in August, after he went to Syria in what he described as a plan to launch a security company.

Mr Goto, a veteran war correspondent, went into Syria in late October seeking to secure Mr Yukawa's release, according to friends and business associates.

Originally posted at 8.45am