About 100 protesters occupied the Mexican side of an international bridge that links the Mexican city of Nuevo Laredo and the U.S. city of Laredo.

    Obrador has called a national demonstration with the demand for a ballot-by-ballot recount of the June 2 election after the official figure showed he had lost the election to ruling National Action Party candidate Felipe Calderon by less than 0.6 percent.

    He has filed a court challenge to the count results, saying his party has found altogether 72,000 polling stations as suspicious and the vote was rigged.

    His party has announced more blockades of international bridges in Mexico's border regions with the United States.

    Some local newspapers on Friday published a letter to the country's top electoral court, the Federal Electoral Tribunal, signed by about 500 celebrities who called for a recount of the election to solve the country's political crisis.

    Among them were filmmaker Luis Mandoki and writers Carlos Monsivasi and Elena Poniatowska.

    To date, there has been no incidents of violence at any demonstration.     

    GOVERNMENT BEEFS UP AIRPORT, POWER PLANTS SECURITY

    Earlier on Friday, the Mexican government said it would reinforce security at the international airport in the capital, some major power plants and oil refineries.

    "Security has been stepped up," said presidential spokesman Ruben Aguilar, noting the government would take the "responsibility where it is responsible" to protect those important places.

    He stressed that the international airport of the capital "will always be in operation."

    The airport authorities had asked for help from the federal government after Obrador's supporters demonstrated at the Acapulco Airport in the southern Mexican state of Guerrero and blocked the entrance to Mexico's Stock Exchange for nearly six hours.     

    FEDERAL ELECTORAL TRIBUNAL TO HOLD FIRST PUBLIC SESSION

    The Federal Electoral Tribunal, after weeks of closed-door deliberations, will hold its first public session slated for Saturday over the election dispute.

    By law, the Federal Electoral Tribunal has to rule on vote disputes by the end of August and announce a winner by Sept. 6. The winner will be sworn in on Dec. 1, taking power from outgoing President Vicente Fox.

    The law allows for limited vote-by-vote recount when there is evidence of irregularities in specific polling stations.

    Seven judges from the tribunal will begin by ruling on 174 allegations of fraud in the election filed by lawyers of Obrador, and those rulings are likely to give yes or no to a full or partial recount.

    Gerardo Fernandez, a spokesman for Obrador's Democratic Revolution Party, said he hoped the court could make the decision on his party's recount request before Monday.

    He also said only a full recount could end the fraud allegations and questions about the country's electoral system.

    Obrador, former mayor of the capital, promises to raise millions out of poverty by slashing spending on government bureaucracy, expanding welfare programs and cutting energy prices.

    His opponent, Harvard-educated Calderon, pledges to reduce crime, extend government health and service programs, create jobs and continue the prudent fiscal policies carried out by Fox. Enditem