Venezuelan troops have used tear gas and water cannon to disperse thousands of students in the capital, Caracas.
Demonstrators are angry about Chavez's reform proposals
The students are demonstrating against constitutional reforms proposed by Venezuela's President Hugo Chavez.
One of the reforms would abolish term limits for the presidency, thus allowing President Chavez to stand for re-election indefinitely.
The students want a December referendum on the reforms to be postponed, to give voters more time to study the plans.
Leaders of the protest have been granted a meeting with Tibisay Lucena, the president of the National Electoral Council to discuss their demands.
The protest follows a similar demonstration on 24 October, in which at least five demonstrators suffered minor injuries after riot police acted to disperse the crowds.
Bypassing legal controls
In addition to abolishing presidential term limits, President Chavez is also proposing to bypass legal controls on the executive during a state of emergency, bring in a maximum six-hour working day, cut the voting age from 18 to 16, and increase presidential control over the central bank.
The Venezuelan congress - dominated by Chavez supporters - recently voted through the reform package.
If the reforms are approved in the December referendum, then they will become law.