Venezuela's Hugo Chavez has been re-elected for his fourth term as president.

He defeated challenger Henrique Capriles, who was the opposition's best chance of unseating him in 14 years.

Mr Chavez's victory could extend his rule of the OPEC member state to two decades.

Jubilant supporters poured onto the streets of Caracas to celebrate the victory. There was relief too among leftist allies around the region from Cuba to Bolivia, who rely on his oil-financed generosity.

The 58-year-old took over 54% of the vote, with 90% of the ballots counted, compared with almost 45% for young opposition candidate Mr Capriles.

More than 80% of registered voters cast ballots.

The victory was considerably slimmer than his win by 25% in 2006, reflecting growing frustration at his failure to fix problems such as crime, blackouts and corruption.

In a nod to those complaints, Mr Chavez said he would be more focused in his new term beginning on 10 January.

"Today we start a new cycle of government, in which we must respond with greater efficacy and efficiency to the needs of our people," he said. "I promise you I'll be a better president."

Mr Chavez has become Latin America's main anti-US agitator, criticising the US while getting close to its adversaries, including Cuba, Syria and Iran.

A decade-long oil boom has given him tens of billions of dollars for social investments that range from free health clinics to newly-built apartment complexes, helping him build a strong following among the poor.

Following this victory, Mr Chavez could order new nationalisations in some largely untouched corners of the economy, including the banking, food and health industries.

He took advantage of his landslide win in 2006 to order takeovers in the telecoms, electricity and oil sectors.

A subdued and tired-looking Mr Capriles accepted defeat in a speech at his campaign headquarters.

He told his supporters: "I hope a political movement that has been in power for 14 years understands that almost half the country does not agree with it."