Venezuelans have rejected President Hugo Chavez's bid to win new powers and run for re-election for decades to come in an unprecedented defeat that could slow his socialist revolution in the OPEC nation.

    In a fiercely contested referendum on Sunday, voters said "No" to reforms that would have scrapped term limits on Chavez's rule, given him control over foreign currency reserves and boosted his powers to expropriate private property.

    Chavez conceded defeat shortly after election officials said early on Monday that the "No" camp had about 51 percent of the vote and that the president scored only around 49 percent support.

    Although he remains powerful and popular, it was the biggest vote blow to the anti-U.S. leader since he swept to power in a 1998 election.

    Students, rights and business groups, opposition parties, the Roman Catholic Church, former political allies and even his usually loyal ex-wife all lined up against Chavez ahead of the referendum vote on Sunday.

    They accused him of pushing the constitutional reforms to set up a dictatorship.

    Enough voters also balked at giving more power to a firebrand leader who calls Cuban leader Fidel Castro his "father," capitalism an evil and himself "El Comandante."     Admired as a champion of the poor in city slums and rural villages, the 53-year-old Chavez has said he wants to rule until he dies.

    He had warned before Sunday's vote that a defeat could sink his revolution and prompt him to think about a successor. Without a constitutional reform, he will have to step down in 2013.

    It was a major victory for Venezuela's fragmented opposition, which had failed to beat Chavez in almost yearly votes or oust him in a brief coup in 2002, a national oil strike and a recall referendum.

    The victory could embolden opposition leaders to try to block Chavez's plans to install what he calls "21st century socialism," which has involved nationalizing large areas of the economy in the No. 4 oil supplier to the United States.

    Chavez still wields enormous power in a country he has pledged to turn into a socialist state. His supporters dominate Congress, the courts and election authorities.

    Soldiers bark his slogan "homeland, socialism or death" when they snap their salutes. The state oil company spends more on social projects such as building homes than on exploration of some of the biggest deposits outside the Middle East.

    Chavez had tried to make the referendum vote a black-and-white plebiscite on his rule and sought to rally his supporters with warnings that he was under attack from Washington and other foreign enemies.