Hamas claimed that communication with the woman’s captors had recently been restored after several weeks, leading to the discovery of her death.
Abu Ubeida, spokesman for Hamas’s military wing, the al-Qassam Brigades, said another female hostage who the woman was held with had been injured and that her life was endangered.
Israeli authorities believe there are around 60 living hostages remaining in Gaza – and the bodies of dozens of others who are believed to be dead.
The news came as Israel pressed ahead with its operations across Gaza on Saturday.
According to the territory’s Hamas-run health ministry, about 120 people were killed by Israeli airstrikes across the territory in the past 48 hours.
Israel launched a campaign to destroy Hamas in response to the group’s unprecedented attack on southern Israel on 7 October 2023, in which about 1,200 people were killed and 251 others were taken hostage.
Nearly 44,000 people have been killed and more than 104,000 injured in Gaza since then, according to the territory’s Hamas-run health ministry.