Maduro was declared the winner of the election on Sunday by a razor-thin margin over an opponent that voiced fears of vote manipulation.
Fireworks erupted after the National Electoral Council announced that near-complete results showed Maduro had won with just 50.66% of the vote compared to 49.1% for opposition rival Henrique Capriles – a difference of less than 300 000 votes.
"This victory is another tribute to our comandant Hugo Chávez," the 50-year-old Maduro said in front of cheering supporters at the Miraflores presidential palace.
"Today we can say that we had a fair electoral triumph," he added, saying he was open to an audit of the close vote tally.
Named by Chávez as his political heir, Maduro rode a wave of grief for the late leader, who ruled Venezuela for 14 years with a socialist revolution that made him popular among the poor while disenchanting others fed up with the weak economy.
Maduro has vowed to continue the oil-funded policies that cut poverty by almost half to 29% through popular health, education and food programs.
But he also inherits a litany of problems left behind by his mentor: South America's highest murder rate, with 16 000 people killed last year, chronic food shortages, high inflation and recurring power outages.
Opinion polls gave Maduro leads of 10 to 20 points during the campaign, but Capriles – who lost to Chávez by 11 points in October polls – energised the opposition in his second shot at the presidency.
Hundreds of Chavistas began to celebrate in front of the Miraflores presidential palace well before the results were announced, launching fireworks, dancing and holding pictures of Maduro and Chávez.
"This is a very important victory for the future of the country. This is the legacy of our comandante, who is no longer here. But he left us Maduro and he will defend his project," said Rafael Perez Camarero (29).
Pressuring civil servants to vote
Before the results were disclosed, Capriles warned on Twitter that there was an "intention to change the choice expressed by the people". He did not immediately react to the official results announced by the electoral council.
The 40-year-old opposition leader charged that there were attempts to let people vote after polling stations closed. Earlier, he accused the government of pressuring civil servants to vote for Maduro.
Maduro campaign manager Jorge Rodriguez called the tweet "a provocation" while Vice-President Jorge Arreaza – Chávez's son-in-law – warned Capriles to be "very careful".
Both candidates had pledged during the campaign to recognise the vote results.
Capriles had graciously accepted his defeat when Chávez beat him in October polls that marked the opposition's best showing against the late leader. Sunday's result against Chávez's handpicked heir was far closer.
Maduro inherited Chávez's formidable electoral machinery, which helped the late leader win successive elections in 14 years, with government employees often seen handing campaign pamphlets and attending rallies in groups.
Evidence of US interventionism
In the capital's Plaza Bolivar, a historic square known as a gathering point for Chavistas, Maduro supporters chanted "Chávez, we obeyed, we won and we continue!" and "Chávez lives, the struggle goes on!"
After voting in Caracas earlier in the day, Maduro warned there would be no dialogue with the "bourgeoisie" – his term for the opposition – and took a shot at the United States, saying he would present evidence of US interventionism on Monday.
His candidacy was backed by Chávez's leftist allies in the region, especially communist Cuba, whose anaemic economy has been kept afloat by generous oil shipments from a nation sitting on the world's biggest crude reserves. – AFP