Venezuela's opposition is celebrating the results of Sunday's poll, in which it overturned President Hugo Chavez's two-thirds majority in parliament.
A spokesman for the opposition umbrella group, the Table for Democratic Unity (MUD), said he was "very happy".
Near-complete results show the MUD won 65, with Mr Chavez's United Socialist Party (PSUV) gaining 98.
The president later said the election was an "important victory" for the country's socialist revolution.
"They say they won," he said, referring to opposition celebrations.
"Well, keep 'winning' then! It suits me like that," said Mr Chavez.
However, his PSUV will now be unable to pass major bills unaided.
The opposition will be capable of thwarting some of Mr Chavez's key socialist reforms, be they appointments to the Supreme Court or backing for sweeping new laws.
It seems that the president will now have to find some way to work with the opposition representatives in parliament, the BBC's Will Grant in Caracas reports.
This vote could mark either the start of a new era of co-operation or the beginning of another period of bitter confrontation in Venezuelan politics, our correspondent adds.
Sunday's poll was also seen as a test of Mr Chavez's popularity ahead of presidential elections in 2012.
'We are majority!'
Electoral authorities say that the PSUV won 98 seats in the National Assembly, and the MUD 65 - surpassing the key target of 55 required to overturn the PSUV's two-thirds majority. Another party won two seats.
Mr Chavez said that the PSUV had secured 5,422,040 votes and the MUD had won 5,320.175. And he dismissed another 520,000 votes won by a party which broke from the PSUV.
His figures contradicted a claim by the MUD that it had won an overall majority. The MUD said it had won 52% of votes cast, but that changes to electoral districts and voting rules prevented that being translated into parliamentary seats.
However, the breakdown of the popular vote has not been confirmed by the National Electoral Council.
The opposition boycotted poll in 2005 - allowing Mr Chavez's party to sweep up almost all the seats in parliament - so they were almost certain to make some gains.
Opposition supporters greeted the results with jubilation at the MUD's headquarters in Caracas.
They chanted "We are the majority!", hugging and kissing.
The results were only announced several hours after polls closed, despite an automated voting system supposed to supply results quickly - prompting the opposition to accuse electoral officials of stalling.
But election officials - who put turnout for the poll at 66% - put the delay down to a number of tight races.
The new parliament will not convene until early January, leaving Mr Chavez three months to push through any key reforms
2012 should be fun.