Leftist, anti-US indigenous leader Evo Morales took an unexpectedly strong lead in Bolivia"s presidential election, but fell short of the 50 percent needed to avert a second round, according to exit polls.

Morales garnered about 45 percent of the vote, more than 11 points ahead of former president Jorge Quiroga, according to polls conducted by the Mori and Ipsos-Captura institutes. The other six candidates trailed far behind.

Earlier opinion polls showed that Morales had 35 percent voter support.

The 3.6 million voters were also called to cast ballots for the 130 deputies and 27 senators in the national congress.

The newly-elected lawmakers may be the ones who will end up picking Bolivia"s leader. Should none of the candidates pass the 50 percent hurdle, Congress must decide next month which of the top two vote-getters will become the new president.

That could create more political uncertainty in this South American country that has seen two presidents forced from power since 2002.

The two frontrunners offer radically different visions for Bolivia, a landlocked country that is roughly twice the size of France.

Morales, 46, a lawmaker and leader of the coca farmers movement has headed popular protests that played a key role in the collapse of two governments. His campaign to become Bolivia"s first indigenous president was marked by anti-US slogans.

On Sunday, he reiterated his pledge to increase state controls over Bolivia"s key gas resources and to protect coca plantations. Coca is the base ingredient of cocaine, but is also popular with indigenous people, who chew it and use it in traditional ceremonies.

Morales said that if he becomes president, "there will be zero cocaine, zero narco-trafficking but not zero coca."

Critics say that if Morales is elected, Washington might end preferential trade agreements and drop aid to Bolivia, South America"s poorest country.

Speaking after he cast his ballot in Villa Tunari, his bastion in the heart of Bolivia"s coca-growing region, Morales said the government he hopes to lead would cooperate closely with other "anti-imperialists," and reiterated his admiration for Cuba"s communist President Fidel Castro.

In Venezuela, President Hugo Chavez, also a virulently anti-US leader, hailed the election, saying in a television address that Bolivia "is writing a new page in its history."

Quiroga, for his part, said that what Bolivia needed is "change with stability, not a leap into the abyss."

"I voted with confidence," said Quiroga, 45, after casting his ballot in La Paz. "We will be first, we have the project with the largest national presence."

Quiroga, who served as interim president for a year from 2001, is seen as a pro free-market technocrat. He wants to boost ties with the United States and attract more private investment.

Voting is mandatary in Bolivia, but hundreds of people protested Sunday that they had been unable to cast their ballots because their names were removed from voter registries.

Voters also elected for the first time governors for the country"s nine departments. Until Sunday, the governors were chosen by the president.

About 200 observers from 24 countries watched over the polls in this South American country that holds the dubious distinction of the world record for coups -- close to 200 since it broke away from Spanish rule in 1825.