The wife of Japanese hostage Kenji Goto has made her first public appeal for her husband's life.

Rinko Jogo also revealed that she has exchanged several emails with his captors, and in the past 20 hours received one which appeared to be their final demand.

"I fear that this is the last chance for my husband and we now have only a few hours left," she said in the appeal, released Thursday.

She urged the Japanese and Jordanian governments to finalize a deal in which an al-Qaida prisoner would be released in exchange for her husband's freedom.

Another Japanese hostage, Haruna Yukawa, reportedly has been killed by the Islamic State militants.