BRUSSELS, May 2 (Xinhua) -- The European Union expressed its concern on Tuesday about Bolivia's decision to nationalize its natural gas industry.

    The plan by Bolivian President Evo Morales to nationalize the country's natural gas sector may have negative impact on world energy markets, "because the markets are now subject to considerable pressure as far as prices are concerned," EU officials said.

    The Bolivian president unveiled the plan on Monday, ordering all foreign companies to sign new operation contracts within six months or quit the country.

    Under the plan, the state-owned oil company, Yacimientos Petroliferos Fiscales Bolivianos (YPFB), will control all natural gas fields in Bolivia and pay foreign companies for their services.

    Some operators will get about 50 percent of the value of gas they extract, but Bolivia's two largest gas fields insist on giving their operators only 18 percent of the revenue of gas extracted there.

    The European Commission said it expected there would be consultations before any move was taken in Bolivia, which boasts the second largest natural gas reserves in South America after Venezuela.

    Bolivia has a reserve of about 48.8 trillion cubic feet of natural gas, which is being exploited by about 20 foreign firms, including Brazil's government-run oil company Petrobras, Britain'sBG Group PLC, France's Total and Spanish-Argentine Repsol-YPF.

    In response to the plan, the Spanish government said on Monday in a statement that Spain was "deeply worried".

    "The (Spanish) government hopes that during the time given to companies to regularize their current contracts, there will be a process of genuine negotiation and dialogue between the government and companies," said the statement released by the Foreign Ministry.

    On Monday, the army was deployed to guard natural gas fields to enforce compliance.

    Morales, who took office in January as Bolivia's first Indian president, has repeatedly said his country's natural resources must be nationalized so that Bolivians could benefit from the profits that were sent overseas. Enditem