Several hundred thousand opponents of Venezuelan President Hugo Chavez have marched in Caracas in a show of strength aimed at energizing their fight for a referendum to oust the leftist leader.
The huge march, the largest by the opposition this year, followed a week of violent clashes in the capital and other cities between troops and pro-referendum protesters in which at least eight people were killed.
U.S. President George W. Bush said Washington would work with the Organization of American States "to help ensure the integrity" of the referendum process.
His remarks to a news conference at his Texas ranch came a day after the U.S. State Department warned Americans to avoid all demonstrations in Venezuela.
Venezuelan opposition leaders said Saturday's big turnout gave fresh impetus to their campaign for Chavez to submit to a vote to resolve the political conflict that has roiled the world's No. 5 oil exporter for more than two years.
"We don't want bullets, we want votes," said Eduardo Fernandez, a veteran opposition Christian-Democrat politician.
Leaders of the broad anti-Chavez coalition, which brings together businessmen, dissident military officers, middle-class professionals and union militants, called for unity to end political infighting that has weakened the opposition.
Waving national flags and banners reading "down with dictatorship," the marchers denounced what they said were killings and human rights abuses committed by troops in the recent protests. A minute's silence was observed for the dead.
"Our civic resistance must continue in every corner of the country," opposition leader Enrique Mendoza said.
Troops backed by armored vehicles sealed off the presidential palace and the National Electoral Council, the country's election authority. But the march was peaceful.