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A defiant Prime Minister Ariel Sharon (search) said he won't resign despite the humiliating rejection of his Gaza withdrawal plan, and his allies suggested the veteran tactician will look for ways to override the veto of his Likud Party (search).

However, the Likud's resounding "no" in Sunday voting means Sharon's plan of "unilateral disengagement" from the Palestinians will be put on hold for now. Any of Sharon's option to win approval in a different forum — including early elections or a national referendum — would take months to prepare.

Army Radio reported early Monday that with all the votes counted, opponents of the plan had 60 percent, while supporters accounted for only 40 percent.

The vote was marred by violence. Palestinian gunmen killed a pregnant Gaza (search) settler and her four daughters, ages two to 11, in an ambush on her car, firing from close range. Israel killed four Palestinian militants in the West Bank and destroyed a Hamas-affiliated radio station in Gaza in missile strikes.

Sharon lagged in the polls for several days, but analysts said the Gaza shooting attack and the low turnout — only about 50 percent of 193,000 Likud members voted — gave a further boost to opponents, who had run a well-organized campaign.

The disengagement plan envisions an Israeli withdrawal from Gaza, home to 7,500 settlers, and the evacuation of four small West Bank (search) settlements by the end of 2005, along with the completion of a West Bank separation barrier.

The United States expressed veiled disappointment.

"The president welcomed Prime Minister Sharon's plan to withdraw settlements from Gaza and a part of the West Bank as a courageous and important step toward peace," said White House spokesman Scott McClellan. "We will be in consultation with the prime minister and the government of Israel about how to move forward."

Palestinian leaders, who have dismissed Sharon's unilateral plan as an attempt to tighten Israel's hold over large parts of the West Bank, played down Sunday's vote as an internal Israeli matter.

Ordinary Palestinians didn't pay much attention. "If he (Sharon) had won, do you really think the war would end and tomorrow we would have peace?" said Khalil Abu Ali, 48, a restaurant owner in the West Bank city of Ramallah.

In Gaza, the Islamic Jihad group, which carried out the Gaza shooting along with another faction, said Israel would eventually have to leave the territory. "We are sure the enemy will flee from Gaza," said Khader Habib, a leader of the group.

Israeli opponents of Sharon's plan have said he was surrendering to Palestinian violence. For decades, Sharon was the foremost champion of settlement expansion and led a hawkish line in Likud.

Sharon's allies in the party warned that the Likud was becoming increasingly less appealing to moderate Israeli voters and could get hurt in the next election. Opinion polls have shown a majority of Israelis support the withdrawal plan.

Justice Minister Yosef Lapid of the centrist Shinui Party noted that the number of voters in the referendum amounted to roughly one percent of the Israeli population. "They shouldn't decide the fate of the country," he told Israel Radio.

Vice Premier Ehud Olmert, a Sharon confidant, said disengagement is inevitable and that the prime minister Sharon is determined to move forward, though he stopped short of saying how Sharon would override the party's decision. "There is no way to stop this process," Olmert said.

Opponents celebrated their victory. Likud members chose "a no-compromise fight against terrorism" over "loyalty to the prime minister," said Cabinet minister Natan Sharansky.

The low turnout might help Sharon undermine the legitimacy of the result, analysts said. Sharon said in a statement Sunday that he will "respect" the outcome of the vote, but suggested he would not drop the plan.

"The people of Israel did not want me to sit for four years with my hands folded," Sharon said. "I was elected to bring to this nation the calm, peace and security it deserves. I intent to continue to lead the state of Israel according to the best of my abilities, my conscience and my public obligations."

Sharon requires Cabinet approval to move ahead with the plan.

The referendum had originally been conceived as a way to force hard-line ministers, including Finance Minister Benjamin Netanyahu, to support Sharon. With the party opposed, it is unlikely Sharon would get a majority in his Cabinet.

He could rearrange his Cabinet by bringing in the moderate Labor Party, a move that could split Likud. Labor has said it would join only if the attorney general clears Sharon in two corruption probes. The rulings are expected in coming weeks.

Sharon could also opt for early elections, three years ahead of schedule. Or he could hold a national referendum, which would require special legislation that could take months to move through parliament.

The vote might also strain Sharon's relations with President Bush. Last month, the president went out of his way to help Sharon, endorsing the disengagement plan and giving the Israeli leader unprecedented assurances that in a final peace deal, Israel would not have to withdraw from all of the West Bank.

In the Israeli settlements in Gaza, elation was mixed with mourning for 34-year-old Tali Hatuel and her four young daughters. Hatuel, who was eight months pregnant, was en route from Gaza to Israel when her car was ambushed.

Hatuel's husband, David, wept in front of the five graves during the funeral later Sunday in the Israeli coastal city of Ashkelon. "I am all alone, there is no one left," he said in a whisper.

Islamic Jihad and the Popular Resistance Committees, another militant group, said they killed the family to avenge the assassination of Hamas leaders by Israel last month.

In the West Bank city of Nablus, four Palestinian militants from the Al Aqsa Martyrs' Brigades were killed in an Israeli missile strike.