Bolivian demonstrators attend a protest march in San Francisco square in La Paz June 6, 2005. The protesters are demanding nationalization of the country's natural gas sector. (Xinhua/AFP Photo)

Bolivian riot police fire tear gas bullets at the protesters in La Paz. (Xinhua/AFP Photo)

Bolivian President Carlos Mesa speaks while addressing the nation in La Paz, Bolivia on Friday, June 3, 2005.(AP Photo)

    LIMA, June 6 (Xinhuanet) -- Bolivian President Carlos Mesa submitted his resignation late Monday to Congress after mass anti-government protesters paralyzed the country's capital of La Paz.

    "It is my responsibility to say that this is as far as it can go." Mesa said on national television. "I have taken the decision to present my resignation from the presidency."

    For several weeks, the protesters are demanding nationalizationof the country's natural gas sector. Bolivia has the second-largest gas reserves in South America, after Venezuela.

    The long-term crisis over the gas issue has already forced Mesa's predecessor, Gonzalo Sanchez de Lozada, to step down 20 months ago.

    Earlier on Monday, the embattled Mesa managed to flee his office after protesters threatened to storm the presidential palace. Enditem