JERUSALEM, Nov 4, 2024 (BSS/AFP) - An Israeli group campaigning for the release of hostages held in Gaza called on Monday for an investigation into the alleged leak of confidential documents by an ex-aide to the prime minister, which may have undermined efforts to secure the captives' release.

An Israeli court announced on Sunday that Eliezer Feldstein, a former aide to Benjamin Netanyahu, had been detained along with three others for allegedly leaking documents to foreign media.

The case has prompted the opposition to question whether Netanyahu was involved in the leak -- an allegation denied by his office.

"The (hostage) families demand an investigation against all those suspected of sabotage and undermining state security," the Hostages and Missing Families Forum said in a statement.

"Such actions, especially during wartime, endanger the hostages, jeopardise their chances of return and abandon them to the risk of being killed by Hamas terrorists."

The forum represents most of the families of the 97 hostages still held in Gaza after they were seized in the unprecedented October 7, 2023, Hamas attack on Israel that sparked the war. The Israeli military says 34 of them are dead.

"The suspicions suggest that individuals associated with the prime minister acted to carry out one of the greatest frauds in the country's history," the forum said.

"This is a moral low point like no other. It is a severe blow to the remaining trust between the government and its citizens."

Critics have long accused Netanyahu of stalling in truce negotiations and prolonging the war to appease his far-right coalition partners.

Israel's domestic security agency Shin Bet and the army launched an investigation into the breach in September after two newspapers, British weekly The Jewish Chronicle and Germany's Bild tabloid, published articles based on the classified military documents.

One claimed a document had been uncovered showing that then Hamas leader Yahya Sinwar -- later killed by Israel -- and the hostages in Gaza would be smuggled out of the territory into Egypt through the Philadelphi corridor along the Gaza-Egypt border.
The other was based on what was said to be an internal memo from the Hamas leadership on Sinwar's strategy to hamper talks towards the liberation of hostages.

The Israeli court said the release of the documents ran the risk of causing "severe harm to state security".

"As a result, the ability of security bodies to achieve the objective of releasing the hostages, as part of the war goals, could have been compromised," it added.

On October 7, 2023, Hamas militants attacked southern Israel, resulting in the deaths of 1,206 people on Israeli soil, mostly civilians, according to AFP's count based on official Israeli data, including hostages who died or were killed in captivity in Gaza.

Israel's retaliatory military offensive in Gaza has so far killed at least 43,341 people, a majority of them civilians, according to the territory's health ministry. The UN considers these figures as reliable.