AMMAN (AFP) - The United Nations Security Council demanded the immediate release of all hostages held by the Islamic State in Iraq and Syria (ISIS), as Jordan vowed to do everything it can to save the life of a pilot captured by the militants.
The 15-member council condemned on Sunday the "heinous and cowardly" murder of a Japanese journalist after the militant group claimed he had been beheaded.
"Those responsible for the killing of Kenji Goto shall be held accountable," the Security Council said, demanding "the immediate, safe and unconditional release of all those who are kept hostage" by ISIS and other Al-Qaeda affiliates.
The government of Jordan, meanwhile, vowed to do it all it can to save air force pilot Maaz al-Kassasbeh, who was captured by ISIS after his plane crashed in Syria in December.
ISIS militants have seized swathes of territory in Iraq and Syria, ruling with a brutal version of Islamic law. The group has murdered both locals and foreigners, including two US journalists, an American aid worker and two British aid workers.
ISIS claimed in a video released online on Saturday that it had killed 47-year-old Mr Goto - the second purported beheading of a Japanese hostage in a week - but made no mention of the Jordanian pilot it had also threatened to kill.
Jordan's King Abdullah II denounced Mr Goto's murder as a "cowardly, criminal act" and said every effort was being made "to seek the release of the hero pilot Maaz Kassasbeh".
ISIS has been demanding the release of an Iraqi militant on death row in Jordan in exchange for Mr Kassasbeh's life, and Amman said it would hand her over if given proof he is still alive.
The pilot's father Safi Kassasbeh has begged Amman to save his son's life "at any price".
In Japan, Prime Minster Shinzo Abe condemned the "heinous and despicable terrorist acts" of ISIS and vowed that his country would "never yield to terrorism".
"We will never forgive terrorists," Mr Abe told reporters in Tokyo, appearing to fight back tears as he spoke.
"We will cooperate with the international community to make them atone for their crimes."
In a statement, Mr Goto's wife Rinko said she was "devastated" by the news.
"While feeling a great personal loss, I remain extremely proud of my husband who reported the plight of people in conflict areas like Iraq, Somalia and Syria," she said.
"It was his passion to highlight the effects on ordinary people, especially through the eyes of children, and to inform the rest of us of the tragedies of war."
The couple had a second child just weeks before Mr Goto left for Syria late last year in a bid to find his friend Haruna Yukawa, whom ISIS claimed it beheaded last week. He was then captured himself.
"I can't find the words to describe how I feel about my son's very sad death," Mr Goto's sobbing mother Junko Ishido told reporters.
Officially pacifist, Japan has long avoided getting embroiled in Middle East conflicts and is rarely the target of religious extremism, so the hostage crisis has been especially shocking for the country.
Many braved Tokyo's chilly streets to pick up the Yomiuri newspaper's special supplement about the Goto video on Sunday.
"It's scary - they (the militants) are saying they'll target Japanese people now," said 21-year-old university student Kyosuke Kamogawa. "That sends chills down my spine."
On Sunday, ISIS added to its long list of atrocities by claiming to have beheaded an Iraqi police officer and a soldier, according to pictures posted online.