The leader of Palestinian fighters group Hamas, Ismail Haniyeh, on Wednesday accused Israel of committing "massacres" in the Gaza war to cover its own "defeats".

Haniyeh, whose Islamist group launched the bloody October 7 attacks on Israel that sparked the Gaza war, accused Israel of "committing barbaric massacres against unarmed civilians".

"Its villainy will not save them from resounding defeat," he vowed in a speech broadcast by Al Jazeera.

The health ministry in Hamas-run Gaza said Wednesday that 3,648 children are among 8,796 people killed in Israeli strikes since the war erupted.

The weeks of Israeli bombardment and more recent ground incursions came in response to attacks by Hamas militants which killed around 1,400 people in Israel, the majority civilians, according to Israeli officials.

Haniyeh said that ahead of the October 7 attacks, Hamas had warned that Israeli Prime Minister Benjamin Netanyahu "and his fascist government will continue their contentious policies".

Netanyahu took office late last year at the head of a coalition that includes extreme-right ministers who live in settlements in the occupied West Bank that are deemed illegal under international law.

The Hamas leader cited the expansion of Israeli settlements in the West Bank, settler violence and attacks on holy sites including the Al-Aqsa mosque in annexed east Jerusalem.

The self-exiled Hamas leader also stressed that there will be no regional stability unless Palestinians obtain their "legitimate rights to freedom, independence and return".

The question of return refers to descendants of the 760,000 Palestinians who fled or were expelled from their homes during the 1948 war that accompanied Israel's creation.