Venezuelan President Hugo Chavez has narrowly lost a referendum on controversial constitutional changes.
Voters rejected the sweeping reforms by a margin of 51% to 49%, the chief of the National Electoral Council said.
Mr Chavez described the defeat as a "photo finish", and urged followers not to turn it into a point of conflict.
Correspondents say the opposition could barely hide their delight and that the victory will put the brakes on Mr Chavez's "Socialist revolution".
With his raft of reforms, Mr Chavez was seeking an end to presidential term limits and the removal of the Central Bank's autonomy.
But the result marks the president's first electoral reverse since he won power in an election in 1998.
Since then he has set about introducing sweeping changes in the country's laws aimed at re-distributing the Venezuela's oil wealth to poorer farmers in rural areas.
The main opposition parties had claimed during the referendum campaign that Mr Chavez was seeking to give himself too much power, and was trying to establish a dictatorship.
BBC NEWS | Americas | Chavez defeated over reform vote