Highways connecting Bolivia with Argentina, Paraguay, Peru and Chile were blocked by demonstrators after a nationwide unrest paralyzed traffic within the country, the Bolivian National Road Service (SNC) said Wednesday.

The SNC's road maintenance chief Carlos Ferreira said demonstrators set up roadblocks at 41 points in six of the country's nine provinces within hours.

He said the highways from La Paz, seat of Bolivia's government, to the border cities of Peru, Chile, Argentina and Paraguay were blocked by demonstrators, mostly farmers.

In La Paz, only a road leading to the tourist resort of Yungas remained available despite threats of blockages, Ferreira said.

He told reporters that the southern city of Potosi had been isolated and protesters were reportedly trying to do the same in other main cities like Santa Cruz and Cochabamba.

Protesters took to the streets after the parliament passed a law on May 17 to levy a 50-percent tax on foreign oil and gas companies operating in the country, which boasts an estimated 48.7 trillion cubic meters of natural gas, the second-highest reserves in South America after Venezuela.

Opposition first demanded higher taxes on foreign companies and later the nationalization of the lucrative oil and gas industry. They also demanded the resignation of President Carlos Mesa, who took office in October 2003.

Demonstration has turned into riots since May 24 when demonstrators blocked a downtown square in La Paz, where the executive and legislative departments are located, and began to smash windows in buildings and cars in the surrounding streets.

Mesa released a statement on Wednesday, calling on the demonstrators to "respect the president of the republic, the national government and people in general."

(Xinhua News Agency June 2, 2005)