The new leader of Israel's Labor Party said Thursday he would fulfill his campaign promise to withdraw from the country's coalition government, arranging to meet Prime Minister Ariel Sharon next week to set a date for early elections.

"We want to leave," Amir Peretz told reporters soon after his surprising victory over Vice Premier Shimon Peres in the race to lead Israel's founding Zionist party. He said the impending departure from Sharon's coalition came from "a desire to turn the Labor Party into an alternative that intends to take power in the next elections."

Peretz signaled in comments throughout the day that he intends to turn Labor, whose 21 seats in Israel's parliament make it the second-largest bloc, into a feisty adversary of Sharon's divided Likud movement.

Peretz's narrow victory in voting Wednesday signaled a shift for the once-dominant party that for much of the past year has played a supporting role to Likud, a hawkish rival headed by Sharon. Twenty-eight years younger than Peres, the new Labor leader is part of an emerging generational change that is reshaping Israeli politics in the wake of Israel's withdrawal from the Gaza Strip and before the next general elections. These are now likely to be held in the spring.

Peretz, 54, heads the powerful Histadrut labor union federation. In his victory speech, he reached out to voters who had moved to Likud. Sharon has embraced a more free-market philosophy and favors a reduction in public spending, a program that was tacitly endorsed by Peres but angered many Labor supporters, who say that approach led to Israel's rising poverty rate.

Peretz said "Likud had left" low-income voters, offering a hint of the campaign he intends to run as the party's candidate for prime minister. He said in his speech, delivered after the election results were announced Thursday morning, that "we will not allow the prime minister to duck responsibility for this."

Speaking to Israel's Export Institute, Sharon said Thursday that his government will "continue our growth-generating policy of liberalization and privatization," adding that his goal is to prepare the economy to expand at an average annual rate of at least 4 percent over the next decade.

Peres, 82, brought Labor into Sharon's coalition last year to support Sharon's planned withdrawal from Gaza. The alliance angered some Labor members because it kept Sharon in power.

In his victory speech in Tel Aviv, Amir Peretz pledged to "turn the Labor Party into an alternative that intends to take power in the next elections."