LIMA, June 13 (Xinhuanet) -- An United Nations observer mission arrived Monday afternoon in Bolivia to assess what assistance the world body can provide to the country within the framework of the political transition.

    The mission, headed by UN under secretary general for economic and social affairs Jose Antonio Ocampo, will meet with President Eduardo Rodriguez to analyze the cause of the resignation of Carlos Mesa as president, and discuss solutions to the political, social and economic problems facing the country.

    The mission will also hold meetings with leaders of political parties and social organizations to prepare for a report that willbe submitted to UN Secretary-General Kofi Annan.

    Rodriguez was sworn in as acting head of state on Thursday after the National Congress unanimously accepted the resignation of his embattled predecessor Carlos Mesa in an emergency session after weeks of unrest in the country.

    The unrest in Bolivia erupted after the National Congress passed a law on May 17 to levy a 50-percent tax on foreign oil andgas companies operating in Bolivia, which has the second largest gas reserves in South America after Venezuela.

    The opposition demands higher taxes on foreign firms and the nationalization of the country's lucrative oil and gas industry.

    Demonstrations escalated into riots on May 24 when demonstrators blocked a downtown square in La Paz, where the executive and legislative branches of government are located, and began to smash windows in buildings and cars in the surrounding streets.

    According to the Bolivian constitution, Rodriguez has to call general elections within six months. Enditem