The video has been published by Qassam Brigade, and shows three people whose faces are clear on the recording. Two of them are people who were released by Hamas in February. The third person urges the Israeli government to set him free.
The film is accompanied by a message: "Only a deal on a ceasefire will let them survive".
Israeli media identify the hostage as Eitan Horn, brother of Iair Horn who was previously released in an exchange of Palestinian prisoners for hostages.
The relatives of Eitan Horn have approved the publication of the video.
It is with sorrow that we see Eitan in this difficult situation, when he says goodbye to his brother Iair who was released while Eitan remains in Hamas captivity – now for 512 days, said the family in a statement.
The office of Prime Minister Benjamin Netanyahu chose to comment on the published video on Saturday, and wrote that Israel "will not be deterred by Hamas propaganda".
