Bolivia's Supreme Court chief Eduardo Rodriguez was sworn in as new president after his embattled predecessor Carlos Mesa resigned in an emergency session, reports Xinhua.

Rodriguez was sworn in late Thursday after both Senate leader Hormando Vaca Diez and House leader Mario Cossio refused to accept the post in succession, said reports from Sucre, the constitutional capital of Bolivia.

Under the constitution, new elections must be held within six months.

In his inauguration speech, Rodriguez did not set a date for early elections. He said: "One of my tasks will be to call an electoral process to renew and continue building a democratic system that is more just."

On Monday, Mesa announced his decision to resign following several weeks of anti-government protests. 

Bolivia has been badly hit by protests and social unrest ever since Congress passed a law May 17 to levy a 50 percent tax on foreign oil and gas companies operating in Bolivia, which has the second largest gas reserves in South America after Venezuela.

The opposition has demanded higher taxes on foreign firms and the nationalisation of the country's oil and gas industry.

The country has been hit by riots since May 24 when demonstrators blocked a downtown square in La Paz, where the executive and legislative branches of government are located, and smashed windows and cars.

In a bid to halt oil and gas production, hundreds of peasants in the eastern Santa Cruz province have blockaded roads and entrances to four natural gas fields operated by foreign firms.