Updated

Evo Morales coasted to victory in Bolivia's presidential elections, winning an unprecedented third term as voters rewarded the former coca grower for delivering economic and political stability in what has traditionally been one of South America's most ungovernable nations.

Morales, a native Aymara Indian, received 60 percent of the vote against 25 percent for cement magnate Samuel Doria Medina, the top vote-getter among four challengers in Sunday's election, according to a quick count of voting stations by the polling firm Ipsos for ATB television. Official partial results were expected early Monday.

Doria Medina conceded defeat late Sunday promising to "keep working to make a better country."

Morales' supporters poured into the streets to celebrate the triumph, but the festive mood was partly dented by an apparent failure by the ruling Movement Toward Socialism party to retain the two-thirds control of Congress needed to push through a constitutional reform lifting a two-term limit on presidential mandates.

In a victory speech from the balcony of the presidential palace in La Paz, Morales dedicated his victory to Cuba's Fidel Castro and the late Venezuelan president, Hugo Chavez.

"It is a triumph of the anti-colonialists and anti-imperialists," Morales said in a booming voice. "We are going to keep growing and we are going to continue the process of economic liberation."

Morales won eight of Bolivia's nine states, including the former opposition stronghold of Santa Cruz, an agribusiness center in the eastern lowlands where he polled 51 percent, according to Ipsos.

Morales is now on track to become Bolivia's longest-serving leader consecutively in office, eclipsing 19th century Marshal Andres de Santa Cruz, a founder of the republic in power from 1829-1839.

While known internationally for his anti-imperialist and socialist rhetoric, the 55-year-old coca growers' union leader is widely popular at home for a pragmatic economic stewardship that spread Bolivia's natural gas and mineral wealth among the masses.

A boom in commodities prices increased export revenues nine-fold and under Morales' watch Bolivia accumulated record international reserves and sold bonds abroad for the first time in nearly a century. Economic growth has averaged 5 percent annually, well above the regional average. A half a million people have put poverty behind them since Bolivia's first indigenous president first took office in 2006.

Public works projects abound, including a satellite designed to deliver Internet to rural schools, a fertilizer plant and La Paz's gleaming new cable car system. His newest promise: to light up La Paz with nuclear power.

Morales had sought Sunday to improve on his previous best showing — 64 percent in 2009 — and to maintain a two-thirds control of Bolivia's Senate and assembly needed to lift term limits.

He has not said whether he would seek a fourth term, only that he would "respect the constitution."

A court ruled last year that Morales could run for a third term because his first preceded a constitutional rewrite. All seats were up for grabs in the 36-member Senate and 130-member lower house. Results were not immediately available but exit polls indicate he fell just short of the needed threshold.

Morales' critics say he spent tens of millions in government money on his campaign, giving him an unfair advantage. And press freedom advocates accuse him of gradually silencing critical media by letting government allies buy them out. Morales didn't attend the campaign's lone presidential debate and state TV didn't broadcast it.

"There is no functional opposition, left, right or otherwise," said Jim Shultz, executive director of the left-leaning Democracy Center based in Bolivia and San Francisco.

Morales has capitalized on his everyman image while consolidating his control over state institutions. He long ago crushed and splintered the opposition, nationalized key utilities and renegotiated natural gas contracts to give the government a bigger share of profits.

His image-makers built a cult of personality around him. Stadiums, markets, schools, state enterprises and even a village bear Morales' name. In the center of the capital, crews are building a second presidential palace, a 20-story center complete with a heliport.

Yet Morales has alienated environmentalists and many former indigenous allies by promoting mining and a planned jungle highway through an indigenous reserve.

And despite Bolivia's economic advancements, it is still South America's poorest country. Nearly one in four Bolivians live on $2 a day, according to the World Bank.

Many analysts think Bolivia depends too much on natural resources and is especially susceptible to the current easing in commodities demand from China.

The underground cocaine economy also gets credit for part of the economic boom. Peru's former drug czar, Ricardo Soberon, estimates its annual revenues at $2.3 billion, equal to about 7 percent of gross domestic product.

Morales promotes coca's traditional uses and claims zero tolerance for cocaine.

But the United States considers Bolivia uncooperative in the war on drugs and has halted trade preferences. Morales expelled the U.S. ambassador and Drug Enforcement Administration in 2008, accusing them of inciting the opposition, and last year he threw out the U.S. Agency for International Development.

"Evo's balancing act will be increasingly tough to maintain," said Michael Shifter, president of the Washington-based Inter-American Dialogue think tank. "Although Evo has proven to be a resourceful and resilient politician, who knows his country well, it would be surprising if the next five years go as swimmingly as the last five."

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Associated Press writers Paola Flores contributed from La Paz and Frank Bajak from Lima, Peru.