JERUSALEM (Reuters) - Israeli Prime Minister Benjamin Netanyahu said on Wednesday that Mohammad Sinwar, Hamas' Gaza chief and the younger brother of the Palestinian militant group's deceased leader and mastermind of the October 2023 attack, Yahya Sinwar, had been killed.

Mohammad Sinwar had been the target of an Israeli strike on a hospital in southern Gaza earlier this month and Netanyahu said on May 21 that it was likely he was dead.

The Israeli leader announced that Sinwar had been "eliminated" in an address to the Israeli parliament as he listed off names of other Hamas officials that Israel had killed over the past 20 months, including Sinwar's brother Yahya.

"In the last two days we have been in a dramatic turn towards a complete defeat of Hamas," he said, adding that Israel was also "taking control of food distribution", a reference to a new aid distribution system in Gaza managed by a U.S.-backed group.

Hamas has yet to confirm Sinwar's death.

Netanyahu's announcement comes as the Israeli military has intensified its war campaign in Gaza after breaking a fragile ceasefire with Hamas in March. Israel has said it aims to dismantle Hamas' governing and military capabilities and secure the release of hostages that are still held in Gaza.

The war erupted on October 7, 2023 when Hamas-led militants stormed out of Gaza, rampaging through southern Israeli communities and killing around 1,200 people, mostly civilians.

More than 250 were captured and taken as hostages into Gaza.

Israel's retaliatory assault on Gaza has decimated the coastal territory, killing more than 53,000, according to health officials in Gaza, and displaced over 2 million Palestinians.

Gazan health officials have said most of those killed have been civilians but have not said how many militants have died. Israel believes it has killed tens of thousands of militants but has not provided any evidence to support those claims.

Israeli military chief Eyal Zamir on May 26 said Hamas had lost many assets, including its command and control centre.

Sinwar was elevated to the top ranks of the Palestinian militant group last year after Israel killed his brother Yahya in combat.

Yahya Sinwar masterminded the October 2023 attack on Israel that triggered the war, now in its 20th month, and was later named the overall leader of the group after Israel killed his predecessor Ismail Haniyeh in Iran.

(Reporting by Alexander Cornwell and Emily Rose; Writing by Ahmed Elimam; Editing by Alison Williams, Aidan Lewis, Ros Russell)