TOKYO — From the prime minister to ordinary people, Japan was shocked Sunday at a video purportedly showing that one of two Japanese hostages of the extremist Islamic State (IS) group had been killed.

 

Prime Minister Shinzo Abe appeared on public broadcaster NHK early Sunday demanding the militants release 47-year-old journalist Kenji Goto unharmed.

 

He said the video was likely authentic, although he added that the government was still reviewing it. He offered condolences to the family and friends of Haruna Yukawa, a 42-year-old adventurer taken hostage in Syria last year.

 

Abe declined to comment on the message in the video, which demanded a prisoner exchange for Goto. He said only that the government was still working on the situation and reiterated that Japan condemns terrorism.

 

"I am left speechless," he said. "We strongly and totally criticise such acts."

 

Yukawa's father, Shoichi, told reporters he hoped "deep in his heart" that the news of his son's killing was not true.

 

"If I am ever reunited with him, I just want to give him a big hug," he said.

 

President Barack Obama condemned what he called "the brutal murder" of Yukawa and offered condolences to Abe. 

 

The UN Security Council issued a statement that "deplored the apparent murder" of Yukawa, declaring that the IS group "must be defeated and that the intolerance, violence and hatred it espouses must be stamped out”.

 

The Associated Press could not verify the contents of the video message, which was removed from websites soon after it appeared and varied greatly from previous videos released by the IS group, which now holds a third of both Syria and Iraq.

 

Goto's mother, Junko Ishido, was sceptical about the voice on the video claiming to be her son's.

 

"I'm petrified," Ishido told NHK. "He has children. I'm praying he will return soon, and that's all I want."

 

Yukawa was captured last summer, and Goto is thought to have been seized in late October after going to Syria to try to rescue Yukawa.