The "sit-in against the dictatorship" is the latest in a month and a half of street demonstrations against President Nicolas Maduro.
Many Caracas businesses were closed Monday and taxi drivers suspended work in anticipation of a city-wide traffic shutdown.
Opposition leaders are demanding immediate presidential elections. Polls show the great majority of Venezuelans want Maduro gone as violent crime soars and the country falls into economic ruin.
The European Union is also calling for Venezuela elections. EU foreign ministers said today that "violence and the use of force will not resolve the crisis in the country."