The family of Hamza, an Israeli Bedouin taken hostage by Hamas-led fighters alongside his father, had been notified of his death following the conclusion of forensic tests, the Israeli military said on Friday.
Earlier this week, it said the bodies of both hostages had been recovered close to those of armed guards from Islamist group Hamas or another Palestinian militant group, adding their deaths did not appear to have been recent and it was not yet clear how they had been killed.
Ceasefire negotiations between Israel and Hamas have been at an impasse for a year. (AP PHOTO)
There was no immediate comment from Hamas.
The recovery of their bodies comes amid renewed efforts by mediators Qatar, the US and Egypt to reach a deal to halt fighting in Gaza and free the remaining Israeli hostages before President-elect Donald Trump takes office on January 20.
The Hostages and Missing Family Forum, the organisation representing most of the families, renewed its call on the Israeli government to conclude a deal with Hamas and bring back the hostages, saying Youssef and Hamza could have been saved through an earlier agreement.
The negotiations have been at an impasse for a year over two key issues.
Hamas has said it will only free its remaining hostages if Israel agrees to end the war and withdraw all its troops from Gaza.
Israel says it will not end the war until Hamas is dismantled and all hostages are free.
Israel launched its assault on Gaza after Hamas fighters stormed across its border 15 months ago, killing 1200 people and taking more than 250 hostages, according to Israeli tallies.
Since then, more than 46,000 people have been killed in Gaza, according to Palestinian health officials, with much of the enclave laid waste and most of the territory's people - displaced multiple times - facing acute shortages of food and medicine due to Israel's actions, humanitarian agencies say.
