"Despite intensive efforts to save his life, the Zionist enemy killed him in another strike a few days ago," said a caption on the video sent out on social media by the Al-Nasser Salah al-Deen Brigades.

The man, who is shown being treated for a wound and is alive throughout the video, is named by the militants and bears a resemblance to one of the images released by the families of the hostages.

The video, seen by AFP journalists, was not dated and could not be independently verified.

Militants seized about 250 hostages during an attack in southern Israel on October 7.

Israel says around 132 are still in Gaza, though at least 27 are believed to have been killed, according to an AFP tally based on Israeli figures.

Hamas's armed wing released a video on Monday announcing the death of two hostages, who were later confirmed dead by their kibbutz.

The families of the captives have formed a powerful lobby in Israel and hold regular demonstrations calling for the government to do more to bring them back.

The October 7 attack also resulted in the deaths of about 1,140 people in Israel, most of them civilians, according to an AFP tally based on official Israeli figures.

Israel's military response has so far killed at least 24,762 in Gaza, around 70 percent of them women and children, according to the territory's health ministry.