Buenos Aires (AFP) - Argentines elected pro-market leader Mauricio Macri as their new president on Sunday, early official results showed, breaking with 12 years of leftist rule in Latin America's third-biggest economy.

The 56-year-old former chairman of Boca Juniors football club is expected to be Argentina's most economically liberal president since the 1990s and has vowed to ease foreign trade and dollar restrictions.

Partial official results with just over 10 percent of ballots counted gave Macri 54.29 percent of the votes with 45.71 percent for his leftist rival Daniel Scioli, 58, echoing exit polls released earlier.

Cheering, dancing crowds of Macri's supporters celebrated at a conference center on the outskirts of Buenos Aires, waving multicolored balloons and white and sky-blue Argentine flags.

Officials from his campaign took to the stage to claim victory, though Macri had yet to appear.

"We have enormous expectations and 100 percent confidence," said 27-year-old Sofia Matricali, a supporter at the rally of Macri's Let's Change coalition.

"The current government has run its course."

Leaders in Scioli's camp did not initially react publicly at the city center hotel where his supporters were gathered.

Macri climbed in the polls after losing closely in the first round vote on October 25 to Scioli, an ally of the combative outgoing president Cristina Fernandez de Kirchner.

That result forced Argentina's first ever presidential runoff.

- End of Kirchner era -

Macri has capitalized on discontent among voters who said they were fed up after 12 years of rule by Kirchner and her predecessor and late husband, Nestor Kirchner.

With social welfare programs and protectionist economic policies, they won affection among poorer Argentines and mistrust among foreign investors.

Macri has vowed to free up trade, liberalize the economy and negotiate with Argentina's foreign debtors.

If confirmed by full results, his victory will break the grip of Peronism, the broad populist movement that has dominated Argentine politics for much of the past 70 years.

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"We have lived too long with Peronism," said Luis Nizzo, an 81-year-old retired engineer, after voting for Macri at a school in Buenos Aires.

"This has been the most corrupt government in Argentina's history."

But Guillermo Juarez, 25, said he voted for Scioli "because of everything they say about Macri -- that he will take away support for working people and cut social welfare programs."

- 'Historic day' -

Voting earlier, Macri told a crowd of reporters and supporters: "It is a historic day that will change our lives."

Scioli said that Macri's proposals threatened Argentines' welfare payments, salaries and industry.

He called on voters to "choose the best path for social, economic and political stability," after casting his ballot.

The increasingly tense campaign was fought on shifting political ground in the vast South American nation of 42 million people.

Macri proposed to immediately lift restrictions on imports and on US dollars.

Scioli warned that would trigger a brutal devaluation of the peso, weakening ordinary Argentines' incomes.

Analysts say Macri may struggle to push his reforms through a hostile Congress.

His rise raised hopes among financiers, but fears among domestic businesses and poorer Argentines who have benefited from the social and trade policies of the combative outgoing president.

Cristina Kirchner had sharp words at times for foreign powers including the United States, and for Britain in the territorial dispute over the Falkland Islands, known in Spanish as Las Malvinas.

After a 2001 financial crisis in which Argentina was bailed out by the International Monetary Fund, the Kirchners presided over a spectacular turnaround, but the economy now seems to be flagging again.

Growth was relatively slow at 2.2 percent in the first half of this year and inflation exceeds 20 percent.