This image obtained from the SITE Intelligence Group on January 24, 2015, shows a still image of Japanese hostage Kenji Goto holding a photograph allegedly showing Haruna Yukawa's slain body. Source: AFP

The apparent beheading of self-employed security contractor Haruna Yukawa was announced in a video posted online.

“Such an act of terrorism is outrageous and unforgivable,” Mr Abe told broadcaster NHK.

“I condemn it strongly and resolutely,” he said, calling for the immediate freeing of Yukawa’s fellow captive, freelance journalist Kenji Goto.

In a city outside Tokyo, Shoichi Yukawa told of the horror he had felt when he learnt that threats to kill his son had been carried out. “I thought ‘Ah, this finally happened’ and was filled with regret. I went totally blank, I was only sorry ... I had no words,” he said.

“In my mind I wish very much that this wasn’t true.”

US President Barack Obama led the worldwide condemnation of what he called Islamic State’s “brutal murder” of Yukawa.

Prime Minister Tony Abbot called it “an absolute atrocity” ­carried out by a “death cult”.

The recording, which lasts nearly three minutes, shows a still image of Goto holding what appears to be a photograph of ­Yukawa’s slain body.

It was posted with an audio ­recording in which a man claiming to be Goto blames Mr Abe for his fellow captive’s death because he failed to pay the $US200 million ($250m) ransom the jihadists ­demanded within 72 hours last ­Tuesday. The voice also reveals a new demand for the release of Sajida al-Rishawi, an Iraqi woman sentenced to death in Jordan for her part in multiple bombings in Amman in 2005 that killed 60 people.

The man, who speaks accented English, said the militants were no longer demanding money to save his life, but wanted “their sister” to be freed.

“It is simple. You give them Sajida and I will be released,” the voice says. “At the moment, it ­actually looks possible and our government are indeed a stone throw away.”

Some commentators have noted that the voice does not resemble that heard on videos featuring Goto. However, one analyst interviewed by Japanese media was reported to have said it was “more than 99 per cent certain” the voice was his.

Japan dispatched a senior minister to Jordan last week. Mr Abe declined to comment on whether he would ask Amman to release Sajida.

The appearance of the video was met with initial scepticism, partly because it was not posted on an official Islamic State channel and does not bear their usual black and white flag. The killing of Yukawa is also not shown. However, the US-based monitoring service SITE said while made in a different style, it was an Islamic State video.

Goto’s mother, Junko Ishido, said yesterday she was left with ­little hope after seeing the picture of her son, in which he “looked very tense”. “Japan never abandons its ­people,” she said. “I believe the government is united and doing its best.”

Islamic State, which rules large swaths of Iraq and Syria, has murdered five Western hostages since last August, but this is the first time it has threatened Japanese.

One adviser to Mr Abe reportedly said there had been some “indirect” communication with the militants, but “nothing direct”.

Islamic State linked its ransom demand to the amount Mr Abe said he would earmark to help countries dealing with the influx of refugees fleeing fighting between Islamic State militants and regular forces.

AFP