Prime Minister Benjamin Netanyahu vowed on Sunday to keep fighting in Gaza, even as anguish over the Israeli military’s accidental killings of three hostages in the enclave raised new questions about how his government is prosecuting the war.

Amid a mounting outcry over the civilian toll in Gaza, the U.S. defense secretary, Lloyd J. Austin III, is traveling to the Middle East this week. Mr. Austin is expected to voice support for Israel’s campaign to destroy Hamas in Gaza but also to reinforce the importance of taking civilian safety into account during operations, according to a senior Pentagon official said.

Mr. Netanyahu began a government meeting in Tel Aviv on Sunday by reading from a letter that he said came from families of Israeli soldiers killed fighting in Gaza.

“You have a mandate to fight; you do not have a mandate to stop in the middle,” Mr. Netanyahu read in Hebrew, according to a statement from his office.

As a “testament” to the fallen soldiers, Mr. Netanyahu said, Israel’s military would “fight to the end.”

The letter appears at odds with the message coming from relatives of Israelis still held hostage in Gaza, many of whom have taken to the streets to demand a cease-fire so that their loved ones can return home.

Weekly rallies in support of the hostages have drawn thousands of protesters to Tel Aviv to demonstrate outside the Israeli military’s main headquarters. News that the Israeli military had mistakenly killed the three hostages on Friday added a sense of urgency to the rally on Saturday night.

Hundreds of protesters gathered on a central boulevard in Tel Aviv to demonstrate against the government before marching through the city to join the hostage rally.

“We see the current approach is not working,” said Deborah Galili, a protester from Tel Aviv. She said she wanted Mr. Netanyahu’s government to pursue a peaceful resolution that would bring the hostages home and end the fighting.

A weeklong cease-fire between Israel and Hamas last month saw 105 hostages freed in exchange for the release of Palestinians from Israeli jails before negotiations broke down and the war resumed on Dec. 1.

But since then, Ms. Galili said, “we’re not seeing more hostages coming home alive.” Several hostages have been confirmed dead by Israel’s military in recent weeks.

Ahal Besorai’s niece and nephew were among those released during the pause, but their father — Mr. Besorai’s brother-in-law — remains in captivity. Mr. Besorai said in a phone interview on Sunday that he understood why people were demanding a cease-fire, especially after the deaths of three hostages, but worried that only military pressure will bring the rest of his family home.

“It’s a very, very, very, difficult spot because on the one hand, you want your loved one to be released, and on the other hand, you want Hamas eliminated,” said Mr. Besorai, whose sister was killed in the Oct. 7 attacks. “These two aims and goals of this war appear at times in conflict.”

Some protesters said that they believed the accidental killings of the three hostages by Israel’s military would mark a turning point in people’s willingness to publicly criticize Mr. Netanyahu and the way his government is handling the war.

Ms. Galili was one of them.

“Mr. Netanyahu has not taken responsibility,” she said, adding that he needs to “step up” and take responsibility or step down.

Efi Toledano, another demonstrator from Tel Aviv, had protested Mr. Netanyahu’s government before the war. While he stopped in wake of the Oct. 7 attack on Israel, the deaths of the hostages prompted him to resume protesting on Saturday night.

“We were taught that when there’s a war, we are all to be quiet and support the soldiers,” said Mr. Toledano. He said that the deaths of hostages suggested that Mr. Netanyahu might be interested in continuing the war even at the expense of hostages’ lives. Because of that, he added, “We are returning to sound our voice and fight against this government.”

A correction was made on 

Dec. 17, 2023

An earlier version of this post misstated the nationalities of the 105 hostages freed. They were not all Israelis.

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