
Israeli Prime Minister Benjamin Netanyahu said he had instructed the military to intensify pressure on Hamas after the group rejected an Israeli proposal for another temporary truce.
In a late-night televised address, Netanyahu said that while war came with a heavy price, Israel had "no choice but to continue fighting for our very existence, until victory".
Egyptian mediators have been working to restore the ceasefire, which Israel abandoned last month after seeking to extend a temporary truce that had seen 38 hostages released.
Hamas has said it would only free the remaining hostages under a deal that ends the war.
Earlier on Saturday, Hamas said that it had recovered the body of a guard killed in an Israeli air strike this week and who was holding Edan Alexander, an Israeli dual national soldier believed to be the last American citizen held alive in Gaza. The fate of Alexander was unknown, Hamas said. Netanyahu did not mention Alexander in his remarks.
US President Donald Trump's envoy Steve Witkoff said in March that freeing Alexander, a 21-year-old New Jersey native who was serving in the Israeli army when he was captured during the October 7, 2023 attacks, was a "top priority". His release was at the centre of talks held between Hamas leaders and US negotiator Adam Boehler last month.
Hamas had said on Tuesday that it had lost contact with those holding Alexander after their location was hit in an Israeli attack.
A US State Department spokesperson had no comment on the status of Alexander, but reiterated that Hamas must immediately release him and all remaining hostages, and that the group "bears sole responsibility for the war, and for the resumption of hostilities".
Fifty-nine hostages are still held in Gaza, fewer than half of them are believed to be still alive.
Israel put Gaza under a total blockade in March and restarted its assault on March 18 after talks failed to extend the ceasefire. Hamas says it will free remaining hostages only under an agreement that permanently ends the war; Israel says it will agree only to a temporary pause.
Since renewing its attacks, Israel has seized swathes of Gaza and ordered hundreds of thousands of residents to evacuate in what Palestinians fear is a step towards permanently depopulating swathes of land. The Gaza health ministry says 1,600 people have been killed in the past month.
Palestinian health officials said the military had escalated its strikes across the Gaza Strip, killing at least 92 people in the past 48 hours, at least 50 of them on Saturday.
On Friday, the Israeli military said it hit about 40 targets across Gaza over the past day. The military on Saturday announced that a 35-year-old soldier had died in combat in Gaza.
The war was triggered by Hamas' October 7 attack on southern Israel in 2023, in which 1,200 people were killed and 251 taken hostage to Gaza, according to Israeli tallies. Since then, more than 51,000 Palestinians have been killed in the Israeli offensive, according to local health authorities.