Bolstered by a resounding election victory, Prime Minister Ariel Sharon on Wednesday called for national unity against "the murderous hatred" of Palestinian militants, but his efforts to form a broad coalition government are likely to be thwarted by the defeated Labor party.

Sharon might be forced into an alliance with ultranationalist parties that want to block U.S.-backed peace moves and spur him to even tougher moves against the Palestinians. Israel TV quoted Sharon as saying off-camera that he'd rather call new elections than preside over such a coalition.

Before plunging into weeks of haggling over the coalition, facing a parliament with 13 parties, Sharon savored victory for a few hours. As perhaps Israel's most controversial politician and a man who was once considered unelectable, the 74-year-old veteran of military and political wars pulled off what no prime minister has achieved since founding father David Ben-Gurion in 1961 — calling an early election and winning.

Sharon's Likud doubled its strength, from 19 to 37 seats in the 120-member parliament. Likud's political rival, the center-left Labor, posted its worst-ever showing, dropping from 26 to 19 seats.

Sharon profited from the Israeli electorate's shift to the right in response to 28 months of fighting with the Palestinians. Many Israelis are angry at the Palestinians, believing they lied about wanting peace and responded to a reasonable offer with violence. Voters blamed Labor, which led the failed peace negotiations, for the nation's troubles.

Addressing Likud supporters in Tel Aviv early Wednesday, Sharon said Israelis must unite against external threats. "The differences between us are dwarfed by the murderous hatred of the terror organizations."

Sharon has said he wants to revive his 20-month alliance with Labor, but he did not mention the party by name in his victory speech or offer any policy incentives that might prompt Labor to renege on its campaign promise to stay out of a Sharon government.

In his concession speech, Amram Mitzna, Labor's pick for prime minister, said he would lead a spirited opposition and prepare Labor for the next election. "Politics are a marathon, and we are only in the first few kilometers. It is no shame to be in the opposition, and I promise you that our time there will be short," said the 57-year-old former general, who advocates a quick withdrawal from the Gaza Strip and much of the West Bank.

Yet with Labor's poor showing, there was growing speculation that the party would try to depose Mitzna, the mayor of Haifa, who took the helm of Labor only two months ago.

Yossi Sarid, leader of Meretz, another party associated with peace moves toward the Palestinians, took a pre-emptive step and resigned after his party's poor showing. It dropped to six seats from 10 in the outgoing parliament.

Many Palestinians said they feared a worsening of the Mideast crisis during a second Sharon term. "You have Sharon in a new government, a war against Iraq imminent, the disappearance of the peace process, all these factors," said Palestinian Cabinet minister Saeb Erekat, adding that nonetheless the Palestinians respected Israel's democratic choice.

During the vote, the Israeli military imposed stringent travel bans in the Palestinian areas, including curfews that confined hundreds of thousands of West Bank residents to their homes.

Another big winner in the election was the Shinui party led by pundit-turned-politician Yosef "Tommy" Lapid, who attracted disaffected middle-class voters rebelling against what they perceive as religious coercion by ultra-Orthodox Jewish political parties and an unfair tax burden. With 97.2 percent of the vote counted, Shinui had won 15 seats, emerging as the third-largest party and a possible kingmaker.

Further complicating coalition scenarios, Lapid insisted he'd join only a coalition with Likud and Labor, without religious parties. For Sharon, setting up a secular government would mean breaking a strategic alliance with Shas, an ultra-Orthodox party representing Jews whose families originated in Arabic-speaking countries.

The vote was Israel's fourth national election in seven years, and only 68.5 percent of the 4.7 million-strong electorate cast ballots, the lowest turnout ever. The campaign failed to ignite excitement, both because Sharon's victory was considered inevitable and because Israelis have despaired of a quick fix to the bloody and debilitating conflict.

"I hope he (Sharon) will continue the same way he started. The election was just a pause. He will continue to fight against terror," said Oren Mahlab, 32, a Likud activist.

Sharon was elected several months after fighting erupted, in a landslide over Labor's Ehud Barak, who had offered the Palestinians a state in Gaza and more than 90 percent of the West Bank and Gaza Strip. Negotiations fell apart over the fate of Palestinian refugees and Jerusalem.

Sharon rescinded Barak's offers and has boycotted Palestinian leader Yasser Arafat, convincing the U.S. administration he should be replaced. The Palestinian Authority and its economy have been largely crushed, and Israel too has suffered: tourism has collapsed, the economy has contracted, inflation and unemployment have shot up.

Labor was undermined by the deep antipathy of two key groups. Sephardim, the half of Israel's Jews with Middle Eastern roots, still hate Labor for their treatment in the 1950s, when Labor-led governments were seen as favoring European Jews with subsidies and jobs. Israel's 1 million Russian immigrants, meanwhile, widely associate the left with communism.