The protest in Jerusalem is expected to last four days, with some demonstrators planning to stay in a cluster of tents near Parliament. On Sunday, several carried signs calling for Mr. Netanyahu’s “immediate removal” while others held posters calling for elections, saying “those who destroyed can’t be the ones to fix.”

Elad Dreifuss, a 25-year-old student, said protesting against the government in the midst of wartime was a difficult decision. But, he added, “if the government can’t live up to its responsibility, something has to change.”

Many Israelis have refrained from rallying against the government in the middle of Israel’s military campaign against Hamas.

“We held back for six months,” said Michal Begin, a physician from Jerusalem. “At the beginning, there was a sense that we had to be united for the sake of the war effort.”

But now “many of the reservists are back home, many soldiers have left Gaza,” she added. “Our need to mobilize for the intensive war effort has diminished. Now we can say that this government cannot continue to serve.”

At a news conference in Jerusalem on Sunday night ahead of his scheduled surgery, Mr. Netanyahu hit back at the criticism and demands being made by the protesters.

“Calls for elections now during the war, a moment before victory, will paralyze Israel for at least six months; in my estimate, for eight months,” he said. “They will paralyze the negotiations for the release of our hostages and in the end will lead to ending the war before achieving its goals, and the first to commend this will be Hamas, and that says it all.”

Mr. Netanyahu has come under sharp criticism for refusing to take responsibility for the failures that preceded the Hamas-led attacks on Israel on Oct. 7 and for failing thus far to strike a deal with Hamas to bring home the remaining hostages held by militants in Gaza.

But some worried that the protests could revive conflicts inside Israel that the war had temporarily smoothed over. In the months preceding Oct. 7, Israel had experienced immense domestic strife over a plan backed by Mr. Netanyahu to limit the influence of the judiciary. Huge protests against the effort had been taking place on a weekly basis, with demonstrators accusing the prime minister of trying to undermine the balance of powers and democracy in Israel.

Eitam Harel, a 23-year-old reservist from Jerusalem, watched flag-waving demonstrators gather near Israel’s Supreme Court with mixed feelings.

“Protest is a legitimate and praiseworthy thing,” Mr. Harel said. But he added: “The protests could drag us back to the negative discourse we had before the war.”

Organizers said they were hopeful the protest could shake up the Israeli political system.

“I believe Israel is facing one of the most difficult moments in its history,” Moshe Radman, an entrepreneur who is helping organize the four-day protest, said in an interview. “We need a government that will act for the betterment of the nation, not in the interest of political and personal considerations of a prime minister.”

Despite being on trial for corruption charges, Mr. Netanyahu became prime minister again in late 2022 after spending more than a year in the opposition. His critics have said that the court cases have influenced his decision-making.

Mr. Netanyahu has consistently repelled criticisms of his administration, including its handling of the war. He has asserted that his government was seeking a “complete victory” over Hamas, even though the militant group was still believed to have thousands of fighters nearly six months into the war.

As the first night of the Jerusalem sit-in wore on, some protesters set up tents to sleep in. The Israeli police said they had dispersed a crowd of protesters blocking traffic, making one arrest.

Johnatan Reiss contributed reporting from Tel Aviv.