Tens of thousands of people flooded the streets of the capital Thursday to oppose a referendum that would eliminate term limits for President Hugo Chavez and help him establish a socialist state in Venezuela.

Blowing whistles, waving placards and shouting "Not like this!" the marchers carried Venezuelan flags and dressed in blue — the chosen color of the opposition — as they streamed along Bolivar Avenue.

"This is a movement by those of us who oppose a change to this country's way of life, because what (the referendum) aims to do is impose totalitarianism," said former lawmaker Elias Matta. "There can't be a communist Venezuela, and that's why our society is reacting this way."

The rally marked the close of the opposition's campaign against the proposed constitutional changes, which will be submitted to a vote Sunday. Chavez plans to lead rallies in favor of the reforms Friday.

Venezuelans will vote on 69 proposed changes to nation's 1999 constitution that would, among other things, eliminate presidential term limits, create forms of communal property and give greater power to the presidency.

Chavez denies that the proposals are a bid to seize unchecked power, saying the constitutional overhaul is necessary to give more of a voice to the people through community-based councils.

Rallies for and against the amendments have surged across this South American country in the run-up to the vote, occasionally leading to clashes. There were no immediate reports of violence Thursday.