Israel has not achieved all its military goals in Gaza, the country's Chief of Staff Herzi Halevi, who resigned on Tuesday said.
"The objectives of the war have not all been achieved," he said.
Halevi said he would resign on March 6, taking responsibility for the massive security lapse on Oct. 7, 2023, when Hamas carried out a cross-border attack on Israel.
Halevi, who had been widely expected to step down in the wake of Oct. 7, said he would complete the Israel Defense Forces' inquiries into Oct. 7 and strengthen the IDF's readiness for security challenges. It was not immediately clear who would replace Halevi, who said he would transfer the IDF command to a yet-to-be-named successor.
Despite public anger over Oct. 7, Prime Minister Benjamin Netanyahu's government has resisted calls to open a state inquiry into its own responsibility for the security breach that resulted in 1,200 Israelis killed and about 250 hostages taken.
"On the morning of Oct. 7, the IDF failed in its mission to protect the citizens of Israel," Halevi wrote in his resignation letter to Defense Minister Israel Katz.
Halevi was in lockstep with former defence minister Yoav Gallant, who was fired by Netanyahu in November, and at loggerheads with some ministers over military conscription exemptions given to ultra-Orthodox Jewish seminary students.
After 15 months of attacks on Gaza, the first phase of a cease-fire deal with Hamas went into effect on Sunday, with three hostages being released among a planned 33 in the next six weeks. Some 94 hostages are believed to remain in Gaza, though some may have since died in captivity.
Katz thanked Halevi for his contributions to the military and that he would continue to fulfill his duties until a successor was named, while there would be an orderly search for his replacement. Netanyahu also accepted Halevi's resignation.
Halevi was often criticized by hardliners in Netanyahu's government including Finance Minister Bezalel Smotrich, who said his conduct of the war in Gaza was too soft.
More than 46,000 Palestinians have been killed in Israeli attacks since October 2023 and the blockaded Palestinian enclave has been widely demolished by Israeli bombardments and airstrikes.