Political opponents of President Hugo Chavez marched through Venezuela's capital on Saturday demanding that elections authorities take measures to guarantee a fair presidential vote in December.

Waving placards reading "Open the Ballot Boxes!" and chanting anti-Chavez slogans, roughly 300 protesters marched across Caracas to the National Elections Council.

Opposition leaders hoping to challenge Chavez in the Dec. 3 election argue the council is biased in favor of the current president.

CountryWatch: Venezuela

"We have to fight for clean elections," said Oscar Perez, a leader of the National Resistance Commando, an opposition group. "We don't want to be clowns in the circus directed by the National Elections Council."

Opposition groups are calling for an independent audit of voter rolls and other measures to guarantee transparent balloting.

"We know the council is pro-Chavez, but that can't stop us in our initiative to obtain the necessary conditions for a transparent vote," said Martina Jimenez, a 45-year-old housewife.

Directors of the council, which was appointed by the Chavez-dominated National Assembly, have rejected suggestions the institution is biased and pledged to ensure a fair election.

Several opposition candidates have threatened to boycott the election if the council fails to meet their demands.

Government officials have accused the United States of urging the opposition to boycott the election as part of a larger plan to cause political upheaval in the world's fifth-largest oil exporter.

U.S. officials reject the allegations and Chavez foes deny taking orders from Washington.