Prime Minister Ariel Sharon's (search) moderate new government survived its first test Wednesday, winning a crucial parliamentary vote that had threatened to derail the planned Gaza withdrawal.

But powerful rebels in Sharon's Likud Party who oppose the pullout warned that they would topple the government in the coming months if the prime minister doesn't hold a national referendum on the proposal.

Also Wednesday, five Palestinian militants and an Israeli civilian were killed in separate clashes in the West Bank (search) and Gaza Strip (search).

Wednesday's political crisis revolved around passage of Sharon's 2005 state budget. The spending plan must pass three parliamentary votes by March 31.

Otherwise, the government automatically collapses and new elections would be scheduled, putting the Gaza pullout, which is scheduled to begin in July, in jeopardy.

Sharon this week formed a new government with the moderate Labor Party and a small ultra-Orthodox party. The alliance, backed by several opposition parties, gives Sharon a solid majority in favor of the Gaza withdrawal, despite objections from 13 hard-line lawmakers in his party.

Without the hard-liners' support, however, Sharon will not have enough votes to push his budget through parliament. Some of the opposition parties that back the withdrawal oppose Sharon's 2005 spending plan.

After a meeting, the Likud rebels decided to support the budget in Wednesday's vote. However, they warned they might oppose the budget in the subsequent votes if Sharon does not hold a referendum.

"It was decided unanimously to support the budget until the second and third readings," Yehiel Hazan, a leader of the hard-liners, said shortly ahead of the 64-53 vote. "We call on the prime minister to reconsider holding a referendum."

Sharon has dismissed a referendum as a stalling tactic. "There is no change in his position," said Asaf Shariv, a Sharon spokesman.

Sharon's plan, which includes the evacuation of four West Bank settlements, would uproot 8,800 settlers. Settler leaders, along with many members of the Likud, the traditional patron of the settler movement, oppose the plan.

Israeli military officials have expressed growing concern that a majority of settlers could resist withdrawal and turn to violence. Military officials said Wednesday the army will mobilize several thousand troops during the evacuation.

An extra army division will be deployed in Gaza in June, a month before the withdrawal is to begin. The operation will be called "Brethren Dwelling," a phrase from the Book of Psalms.

The evacuation will begin in the Netzarim settlement in Gaza to test the level of opposition, the officials said. The withdrawal from Gaza will take two months. The four settlements in the northern West Bank will be evacuated in September.

The army is preparing 4,000 large freight containers to move settlers' possessions if they refuse to be evacuated.

Sharon has said Israel's continued presence in Gaza, which was captured in 1967, is untenable. About 8,200 settlers live amid 1.3 million Palestinians in the volatile area, and Palestinian militants attempt to attack Jewish settlements daily.

Sharon proposed the Gaza plan early last year as a unilateral move.

But with this week's election of Mahmoud Abbas (search), Sharon has said he will consider coordinating the pullout with the new Palestinian leader. Sharon refused to negotiate with the late Yasser Arafat, accusing him of encouraging terrorism.

Abbas is trying to win a promise from Palestinian militants to halt attacks on Israel. A top Hamas leader said the Islamic militant group has no plans to disarm and that Abbas has no authority to order an end to attacks on Israel. However, the threat appeared to be largely a negotiating tactic.

Abbas hopes to restart peace talks with Israel. But Israel wants Abbas to crack down on militants before resuming negotiations. Abbas has resisted calls to confront militants, preferring instead to persuade them to halt attacks.

Also Wednesday, Islamic militants detonated at least two bombs near the Jewish settlement of Morag in Gaza, killing an Israeli civilian and wounding three soldiers, one moderately, the Israeli army said.

Islamic Jihad, a violent group that has carried out dozens of attacks on Israeli targets, claimed responsibility, adding that three of its members were killed in an ensuing gunbattle.

In searches afterward, troops found that the entire area was booby-trapped with more explosives that did not go off, the army said.

In the West Bank, two Hamas members were killed in an army operation in a West Bank village early Wednesday, the army spokesman said.

Troops entered the village of Karawat Beni Zeit north of Ramallah to arrest the two activists, the army spokesman said. After surrounding a house, fire was opened on the troops and they returned fire, killing two Palestinians, the army said.