President Barack Obama on Saturday condemned the "brutal murder" of Japanese national Haruna Yukawa by the terrorist organization ISIS and offered his condolences to the Japanese people.
"We renew our call for the immediate release of Kenji Goto and all other remaining hostages," the president said in a statement. "We stand shoulder to shoulder with our ally Japan and applaud its commitment to peace and development in a region far from its shores. We will work together to bring the perpetrators of these murders to justice and will continue to take decisive action to degrade and ultimately defeat ISIL."
The news came after a video was released on Saturday purportedly claiming that one of two Japanese hostages has been killed and demanded a prisoner exchange for the other. Japanese officials said Saturday they were investigating the new online message and trying to determine its veracity.
NBC News could not verify the contents of the message, which varied greatly from previous videos released by the terror group that now holds a third of both Syria and Iraq.
ISIS had released a video Tuesday showing hostages Yukawa and journalist Kenji Goto, and said they would be beheaded if the Japanese government didn't send a $200 million ransom by a 72-hour deadline.
"If confirmed, the brutal murder of Haruna Yukawa is a barbaric and despicable act," said U.K. Foreign Secretary Philip Hammond in a statement released Saturday. He added, "This only serves to underline the depravity of ISIL: their brutality cannot be allowed to succeed."
The Associated Press and NBCNews contributed reporting to this story.