The news came on the eve of the war’s six-month anniversary on Sunday, when thousands are expected to gather in Israel for more protests.

“For six months we have been in a nightmare,” said Esther Buchstab, the mother of Yagev Buchstab, 34, who was taken from Kibbutz Nirim on Oct. 7, speaking at a vigil in Tel Aviv on Saturday evening in Israel. She added, “We demand that the state do everything to reach a deal, to bring back the living for rehabilitation and the murdered for burial.”

Nearby, in Democracy Square, thousands of antigovernment protesters called on Prime Minister Benjamin Netanyahu to bring home the more than 130 hostages still missing after Oct. 7.

As the protest was wrapping up, a car drove through the crowd of demonstrators in violation of police orders, wounding several people, according to a statement from police on Telegram. It wasn’t clear why the driver drove the car into the crowd, but the driver ignored police orders to stop and passengers in the car could be seen yelling at protesters in video posted on social media.

“‘Destroying Hamas’ and ‘absolute victory’ are meaningless slogans,” Eran Herkevi, 66, an agricultural specialist, said. “There is real pressure to bring back the remaining hostages, otherwise the public will never be able to recover as a society.”

These sentiments were echoed by Sarit Perl, 65, a retiree and the mother of three combat soldiers who are all in their second round of deployments. She called for Mr. Netanyahu to be impeached and for new elections to replace him.

“I’m here today, because there are three things that need to happen now: impeachment, bringing back all the hostages and holding elections,” she said.

Ms. Perl criticized Mr. Netanyahu, who is facing mounting calls for elections and whose home in Jerusalem has been the site of frequent protests, including earlier this week.

“Netanyahu has never functioned as a prime minister,” Ms. Perl said. “But now he appears to be acting to deliberately destroy the chances to succeed in reaching a deal, and nothing in Israel will ever recover as long as he remains in his position.”

Sahar Shapira, 42, said that the death of the hostage, Mr. Katzir, highlighted the urgent need for an agreement to return the hostages. “It is clear to people that the hostages cannot survive,” she said, predicting that “many others like him will return in a similar way.”

In an interview with The New York Times in 2009, after Palestinian rocket attacks led to a deadly three-week Israeli offensive against Hamas in Gaza, Mr. Katzir told a reporter that he had a nagging feeling. “I do not feel any victory,” Mr. Katzir said at the time, when the fighting had ended with a shaky cease-fire. “I still do not feel safe.”

News of Mr. Katzir’s death has inflamed tensions in Israel. In a statement announcing the vigil on Saturday, representatives of the relatives of hostages called on Israelis to gather in Jerusalem on Sunday for a rally marking six months of war.

Families of the abductees have organized rallies in a public plaza near the Israeli military headquarters in Tel Aviv every Saturday to pressure the government to make a deal for their relatives’ return. The gatherings have often converged with antigovernment protests.

Israeli officials are meeting with representatives from Egypt, Qatar and the United States in Cairo on Sunday to pick up discussions on a hostage deal that have been stalled for months. President Biden is pressuring participants to reach an agreement that leads to an “immediate cease-fire” and the return of hostages.

Noam Peri, the daughter of Chaim Peri, 79, who was taken from Kibbutz Nir Oz and who Hamas claimed in December was among five hostages killed in Gaza in an Israeli airstrike, demanded action from the Israeli government. “Mr. Prime Minister, members of the cabinet, this is on you!” she said, adding, “Do not come back without a deal!”