GAZA CITY– Hamas released an animated film yesterday bearing a grisly message for Israel: If it doesn’t meet the group’s demands, an Israeli soldier it has held for nearly four years could return home in a coffin.

The short but sophisticated cartoon — which depicts Sgt. Gilad Schalit’s aging father wandering empty streets with a picture of his son and ends with the words “There is still hope” — is the latest product of Hamas’ growing media machine.

The cartoon — which was widely broadcast on Israeli TV — was remarkable for the personal and callous nature of the appeal on an issue that has profound emotional resonance for many Israelis: the fate of Schalit, who was captured by Gaza militants in June 2006.

The Web site of Hamas’ armed wing, which posted the video, said it was intended to pressure Israelis to accept demands for a prisoner swap.