Japan early on Saturday strongly criticised a recording purporting to announce the execution of a Japanese citizen held by Islamic State militants and demanded the immediate release of another captive depicted as appearing on the image.
Chief Cabinet Secretary Yoshihide Suga, in a brief televised statement, said the recording appeared to show captive Haruna Yukawa being killed.
"This is an outrageous and unacceptable act," Suga said. "We strongly demand the prompt release of the remaining Mr. Kenji Goto, without harm."
Suga read the statement and declined to take questions.