Lieutenant General Herzi Halevi is the most senior Israeli figure to resign over the security breakdown on October 7, 2023, when thousands of Hamas-led militants carried out a land, sea and air assault into southern Israel, rampaging through army bases and nearby communities for hours.

Hamas militants killed some 1200 people, mostly civilians, and abducted another 250. More than 90 captives are still being held in Gaza, about a third of whom are believed to be dead.

In his letter of resignation, Halevi said the military, under his command, had “failed in its mission to defend the State of Israel”.

Halevi, who began what was meant to be a three-year term in January 2023, said his resignation would go into effect on March 6.

Israel had earlier announced a “significant and broad military operation” against Palestinian militants in Jenin. The city has seen repeated Israeli incursions and gun battles with militants in recent years, even before Hamas’ October 7, 2023, attack ignited the war in Gaza.

The latest operation came just days into a fragile ceasefire with Hamas in Gaza that is supposed to last for six weeks and see 33 militant-held hostages released in return for hundreds of Palestinians imprisoned by Israel. Three hostages and 90 prisoners were released on Sunday, when it took effect.

Israel captured the West Bank, Gaza and east Jerusalem in the 1967 Mideast war. The Palestinians seek an independent state encompassing all three territories.

The ceasefire does not apply to the West Bank, which has seen a surge of violence since the start of the war. Israeli troops have carried out near-daily raids that often ignite gun battles.

There has also been a rise in attacks on Palestinians by Jewish extremists — including a rampage in two Palestinian villages overnight Monday — as well as Palestinian attacks on Israelis.

Hamas condemned the Israeli operation in Jenin, calling on Palestinians in the occupied West Bank to step up their own attacks.

The smaller and more radical Islamic Jihad militant group also condemned the operation, saying it reflected Israel’s “failure to achieve its goals in Gaza”. It said it was also a “desperate attempt” by Prime Minister Benjamin Netanyahu to save his governing coalition.

Netanyahu has faced criticism from his far-right allies over the ceasefire, which required Israeli troops to pull back from populated areas in Gaza and envisions the release of hundreds of Palestinian prisoners, including militants convicted of involvement in deadly attacks on Israelis.

The ceasefire has already seen Hamas return to the streets, showing that it remains in firm control of the territory despite 15 months of war that killed tens of thousands of Palestinians and caused widespread devastation.

One of his erstwhile partners, Itamar Ben-Gvir, quit the government the day the ceasefire went into effect, weakening the coalition but still leaving Netanyahu with a parliamentary majority.

Another, far-right leader, Finance Minister Bezalel Smotrich, has threatened to bolt if Israel does not resume the war after the first phase of the ceasefire ends in six weeks.

Israel’s military campaign has killed more than 47,000 Palestinians in Gaza, according to local health authorities, who say women and children make up more than half of the fatalities but do not say how many of the dead were fighters.