The campaign to oust Prime Minister Ehud Olmert shifted to the streets Thursday, with a rally in Tel Aviv drawing thousands of people calling for the embattled Israeli leader's resignation.

Olmert, criticized for his handling of last summer's war against Lebanese guerrillas, appeared to be quashing an incipient rebellion against him in the ranks of his Kadima Party — at least for now.

On Wednesday, Foreign Minister Tzipi Livni, a party heavyweight, called on him to quit, and another top party figure, parliamentary coalition chief Avigdor Yitzhaki, resigned to protest Olmert's refusal to step down.

But other Kadima officials rallied around their beleaguered chief, no doubt mindful that a widespread mutiny could lead to early elections that could land the party on the skids. Polls indicate hawkish former Prime Minister Benjamin Netanyahu, leader of the opposition Likud Party, would win an election.

At the square in front of the Tel Aviv city hall, a banner reading "Failures, Go Home!" hung behind a podium as protesters began streaming in at sundown. Some political demonstrations in the past have attracted hundreds of thousands, and the size of this one was seen as a critical sign of the extent of public anger.

Lawmakers Effie Eitam, a hawk, and Yossi Beilin, a dove, set aside their deep political differences to team up in a joint newspaper column Thursday demanding a shake-up at the top.

"Both of us are convinced Olmert has to go home because of his great failure during the second Lebanon war," they wrote in the column that appeared in the Maariv daily under the headline "Come Protest."

Alon Davidi and 34 other protesters started marching to the Tel Aviv rally Tuesday from the southern town of Sderot, 45 miles away.

"We want as many people as possible to come to the square and say, 'Ehud Olmert go home,' '(Defense Minister) Amir Peretz go home,"' Davidi told Army Radio.

Olmert himself said he intended to stay on to remedy the severe flaws in decision-making and crisis management that a government war probe identified in a scathing report Monday. Olmert was singled out in the report for exceptional censure.

At an emergency Kadima meeting called after Livni's announcement Wednesday, Olmert said he would implement the war report's recommendations "down to the last detail."

"I'm personally in an uncomfortable position, but I'm over 60, and have had a lot of experience. I've learned to take responsibility for my actions," spokesman Jacob Galanti quoted Olmert as saying.

Israel's parliament interrupted its spring recess for a special session Thursday to discuss the war probe.

Ahead of that session, Netanyahu for the first time added his voice to the chorus of calls demanding Olmert's resignation. Later, at parliament, he appealed for new elections.

"We must redress the primary flaw the report identifies — the lack of a seasoned leadership, the lack of responsibility, the inability to make tough decisions and carry them out," he told a sparsely attended deliberation.

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Olmert was in the chamber but was not scheduled to speak.

Vice Premier Shimon Peres of Kadima, speaking on behalf of the government, deflected the demands for Olmert's resignation through a barrage of opposition heckling.

"The probe commission instructed this government to immediately redress what needs to be redressed, and it's doing just that, and will do so without hesitation," Peres said.

The hostilities between Israel and Lebanon erupted on July 12 when members of the guerrilla group crossed into Israel, killed three soldiers and captured two others.

In 34 days of fighting, Israel failed to achieve the two main goals Olmert set: to retrieve the soldiers and crush Hezbollah. Instead, Hezbollah fired nearly 4,000 rockets into northern Israel.

Nearly 160 Israelis and more than 1,000 Lebanese died in the fighting, and Israeli soldiers returned from battle complaining of conflicting orders and shortages of food and ammunition.

The White House said it would not get involved in Israeli politics or address whether Olmert's resignation would hamper efforts to bring peace between Israel and the Palestinians.

"I'm not going to play `should have, would have, could have,"' White House press secretary Tony Snow said. "As you know, the president has a good working relationship with the prime minister. He looks upon him as a man who is committed to a two-state solution and working constructively toward peace. But after that, you get into Israeli politics, and we're not going to do it."

Opinion polls released Wednesday said two out of three Israelis want Olmert out now.

In defecting from Olmert's camp, Livni — a popular figure in Kadima — told the prime minister he had lost the public's support and said she considered herself the rightful successor to lead Kadima.

"I told him that resignation would be the right thing for him to do," Livni told reporters. "I haven't worked and am not working to topple the prime minister. That's a decision he'll have to make."

Livni — a relative political newcomer and a former officer in the Mossad spy agency — is Kadima's most popular politician. The daughter of an underground fighter who fought for Israel's independence, she has quickly risen through Israeli politics in recent years and appears to be Kadima's best hope of retaining power.

Under Israel's parliamentary system, Kadima could switch its leader without losing power. The Israeli prime minister is not directly elected and usually comes from parliament's largest bloc.

But emerging from the Kadima meeting late Wednesday, said the party backed Olmert in his decision not to resign. "The prime minister received here unprecedented support," Peres told reporters.

Only three Kadima officials have publicly broken with Olmert — Livni, Yitzhaki and a minor lawmaker, Marina Solodkin.

Reuven Hazan, a political scientist at the Hebrew University of Jerusalem, said Livni's challenge would have been worse had she threatened to resign or bring down the government.

"We see a ball rolling, but a ball that could have taken on a lot of momentum today has slowed down," he said.

Hazan said the turnout by Olmert's opponents at the rally in Tel Aviv could determine whether the momentum against Olmert grew or fizzled out.