Bolivia's President Carlos Mesa says he has won a crucial five-point referendum allowing more exports of the country's lucrative natural gas reserves.
The result is seen as a confidence vote for President Mesa
Early results show about 75% of voters backing higher taxes on foreign energy firms operating in Bolivia, and large-scale gas exports.
"The five questions have been answered, each one, with a yes," said Mr Mesa.
Victory will secure Mr Mesa's position after riots over the issue unseated the previous government last year.
Mr Mesa still has to win the Bolivian Congress' backing for the referendum result and to negotiate new export contracts for the gas reserves, said to be worth some $70bn.
Natural gas exploitation and export is an explosive issue in Bolivia, where public anger at proposals to ship the gas out of Chilean ports toppled the government last October.
Dozens died in the unrest, triggered in part by a historic antipathy towards Chile, whom Bolivians accuse of stealing the Pacific Ocean ports it controlled before a war in 1879.
Mr Mesa appeared on television declaring the referendum result a triumph for the country, adding that he had never felt so proud of his countrymen.
His supporters have argued that Bolivia, South America's poorest country, badly needs to monetize its untapped gas reserves.
The BBC's Elliott Gotkine in La Paz said that, barring one attempt to burn a ballot box, voting on Sunday was largely trouble-free.
People across the country flocked to their local polling stations, in some cases braving heavy rains and snow to do so.
People braved heavy rains and snow to vote
A day before the poll, about 200 protesters took to the streets. Tyres were burned in El Alto, a city of 800,000 near La Paz.
El Alto was the scene of the mass protests last October, backed by nationalist and indigenous groups and trade unions, which left 80 people dead and unseated the government.
President Mesa dismissed the latest protest as the work of "minuscule radical groups".
The estimated 60% turn-out at the referendum is being viewed as an endorsement of his government.
However, initial official results are not expected until later on Monday or Tuesday and a full vote count is unlikely to be completed before late July.
The Bolivian people were asked five questions, among them whether the gas should be exported.
They were also asked if the state should regain control over the gas sector, which was opened up to private investors in the mid-1990s.
And they voted on whether gas sales should be used as a bargaining chip in any negotiations with Chile in the territorial dispute over access to the Pacific.
Mr Mesa has argued against nationalisation, saying it would frighten off foreign investors.
Those firms have invested several hundred million dollars in gas exploitation in Bolivia in recent years.
BBC Americas analyst James Painter said Mr Mesa believes those firms are the main beneficiaries, which is why they want the reserves - the second largest in Latin America - re-nationalised.