Thousands of Venezuelans are protesting in the capital, Caracas, against President Hugo Chavez's proposed constitutional changes ahead of a national referendum on Sunday.
Opposition parties and student groups gathered in several locations across the capital Thursday before converging in the city center for a massive demonstration.
Venezuelans vote Sunday on the proposed changes that include eliminating presidential term limits and establishing socialist reforms.
The proposals also include giving authorities sweeping powers if a national emergency is declared, including allowing detention without charges and controls on the news media.
Human rights groups and the Roman Catholic Church have condemned the plan. Mr. Chavez, however, still enjoys strong support among Venezuela's poor for lavishing the country's oil income on social programs.
Mr. Chavez's reform package has raised concern among many Venezuelans that he could turn the country into a communist dictatorship.
A recent poll shows that Venezuelan voters oppose the reforms by a wide margin. The polling company Datanalisis announced last week that 49 percent of likely voters oppose the reforms, while 39 percent favor the changes.
Some information for this report was provided by AFP, AP and Reuters.