Mr Chavez has been accused of becoming more authoritarian
Tens of thousands of supporters of Venezuelan President Hugo Chavez have marched in the capital Caracas to celebrate the half-way point of his term in office.
Correspondents say the march was a show of support for the president, following an opposition march earlier this week, calling for a referendum on Mr Chavez's leadership.
Opposition groups delivered a petition to the electoral authorities - signed by more than 2.5 million people - to demand the early vote.
The president told supporters he would not bow to opponents'
efforts to oust him through the ballot box.
Under the Venezuelan constitution, a president can be challenged after serving half his six-year term - a date which Mr Chavez reached on Tuesday.
Mr Chavez said: "Victory is ours, whatever the cost. We are prepared for any sacrifice to fulfil our promise to Venezuela. Long live the revolution."
Salsa music, whistles and drums played as Chavez supporters filled the street.
Many wore red shirts and berets identifying themselves as members of Mr Chavez's "Bolivarian Revolution" - a left-wing movement that the president and his backers claim is aimed at redressing the inequalities of wealth in oil-rich Venezuela.
They joined the president in singing "Happy Birthday, Bolivarian Government".
Mr Chavez has rejected the calls for a referendum. He told the crowds: "The opposition talks about a referendum, but they don't really want one. It's a trick, because they know if there is
one we'll crush them."
He has also insisted that the signatures are fake, and "don't meet constitutional requirements".
The petition signatures will now have to be checked by a new National Electoral Council whose members are due to be named by Venezuela's Supreme Court.
The opposition march on Wednesday was the first large opposition protest since a two-month general strike earlier this year failed to oust Mr Chavez.
Opposition groups say the president, who was elected on promises to bring about economic prosperity in the world's fifth largest oil exporter country, has mismanaged Venezuela's economy.
He is also accused of becoming increasingly authoritarian and dragging Venezuela toward Cuba-style communism.
The crowds enjoyed a festival atmosphere of salsa and drums
But the president - who commands strong support among the country's poor - says a political elite is pushing for his removal to regain the privileges it lost when he took power.
Reuters news agency said recent polls shows Mr Chavez's popularity has slipped as the country's crisis has deepened.
But for "Chavista" Jose Reyes, who received government financial aid for his small shower manufacturing business, the president still represents a chance for change.
"This government works for the benefit of the people. No
one had done that before," he said.