May 4 (Bloomberg) -- Bolivians in the country's wealthiest province approved a ballot measure calling for greater autonomy from the central government, a referendum President Evo Morales said is ``unconstitutional.''

Exit polls in the eastern province of Santa Cruz show the referendum winning about 85 percent support, Bolivian television channels reported. Scattered confrontations between supporters and opponents of Morales took place after voting began this morning, with at least one person killed and 35 injured, the newswire EFE said.

The push for autonomy drew broad support in Santa Cruz, which has been an opposition stronghold since Morales took office in January 2006, promising to nationalize the country's energy industry, divert more natural gas taxes to central government coffers, and break up large landholdings, most of which belong to Santa Cruz farmers.

``It looks like the political opposition in Bolivia is going to have a strong showing,'' Erasto Almeida, a political analyst at the Eurasia Group in New York, said in a phone interview before voting began. ``We'll probably see tensions picking up in the next few months, but I don't think things will degenerate into widespread violence.''

Leaders in Santa Cruz, where Bolivia's oil and gas industry is based, say they should be able to manage their own energy, agriculture and security policies. They also want Crucenos, as the province's residents are known, to have the right to choose the regional governor, a power Bolivia's constitution gives to Morales.

Ballot Question

Voters in Santa Cruz received ballots asking them to answer ``Yes'' or ``No'' to the following question:

``Do you support the ratification and implementation of the Autonomy Statute of Santa Cruz, approved on Dec. 15, 2007, by the provisional autonomy assembly, so that it immediately becomes the law of the land for all those who live in and who carry out public functions in the province?''

The Organization of American States warned last month that the vote could provoke violence. The Washington-based group held an extraordinary session on Bolivia May 2. Former Cuban President Fidel Castro wrote May 1 that Bolivia may ``suffer dramatic events'' because of the referendum, which he said was backed by ``oligarchs.''

Venezuelan President Hugo Chavez, an ally of Morales, called the vote ``a blow to the heart of South America'' during his weekly television show.

`Unconstitutional'

Resistance to Morales has spread to four of the country's other eight provinces, including the gas-rich region of Tarija, on the border with Argentina. Leaders in Tarija, Beni, Pando and Cochabamba are also considering autonomy votes.

Santa Cruz Governor Ruben Costas called the vote a ``revolution without violence'' on April 29, according to the province's official Web site.

Bolivia's National Electoral Court said it is the only agency authorized to oversee elections and that it won't be involved in today's vote. Finance Minister Luis Arce froze bank accounts belonging to the province on April 24, saying the government hadn't received required reports on the region's budget, the newspaper La Razon said.

``I view this as a poll or a survey, not a binding referendum,'' Morales, 48, said in an April 22 interview with Bloomberg Television. ``We're not going to recognize the results because they are illegal and unconstitutional.''

Lower Investment

Morales's efforts to re-take control of the country's energy industry, which include forcing foreign companies to renegotiate their contracts, have led to lower investment amid energy shortages in neighboring Argentina, Brazil and Chile.

Investment in exploration and production in Bolivia's oil and gas industry fell to $149 million last year from $650 million in 2002, the lowest since 1996, according to the Santa Cruz-based Hydrocarbons Chamber. The chamber's members include Petroleo Brasileiro SA, Total SA, and BG Group Plc.

On May 1, Bolivia's national Labor Day holiday, Morales decreed the government was taking majority control of four energy companies and the country's biggest telecommunications provider. The government said it would pay $43.1 million for the energy companies after two years of negotiations failed.

``In the end, both sides have big incentives to reach a political compromise on autonomy, energy policies and taxes, but it will take some time to get there,'' Almeida said.

To contact the reporter on this story: Bill Faries in Buenos Aires at wfaries@bloomberg.net

Last Updated: May 4, 2008 19:29 EDT