Venezuelan opposition leader Maria Corina Machado, from left, Lilian Tintori, wife of jailed opposition leader Leopoldo Lopez and Leopoldo's mother Antonieta Mendoza, attend to a rally against Venezuela's President Nicolas Maduro in Caracas, Venezuela on Monday, April 24, 2017.
The opposition's main demands are for elections, the release of jailed activists and autonomy for the opposition-led congress. But protests are also fueled by the crippling economic crisis in the oil-rich nation of 30 million people.
Anti-government protesters block a highway in Caracas.
Protesters rallied on Monday vowing to block Venezuela's main roads to raise pressure on Maduro after three weeks of deadly unrest that have left 21 people dead.
Artist Marilu Garcia performs a presentation titled "Repressed Venezuela" during the protests.
Trucks burn in flames in Caracas.
PHOTOS: Venezuelans Mount Pressure on Government as Protests Intensify
Opposition activists clash with police forces in Caracas.
Riot police fired rubber bullets and tear gas to break up one of the first rallies in eastern Caracas early Monday while other groups were gathering elsewhere, the opposition said.
Riot police fire tear gas toward opposition supporters during clashes.
Thousands of opposition activists march in Caracas.
This month's turbulence is Venezuela's worst since 2014 when 43 people died in months of mayhem sparked by protests against Maduro, the 54-year-old successor to late leader Hugo Chavez.
Anti-government protesters play cards during a sit-in.
Demonstrators turned the road into a kind of public plaza, settling in for picnics, reading books and reclining under umbrellas to protect against the sun.
An opposition activist participates in a sit-in to block the Francisco Fajardo motorway in Caracas.
Opposition activists set up barricades.
Police officers walk towards anti-government protesters.
An activist sits in front of a burning barricade.
Anti-government protesters throw stones from a highway overpass at a passing police patrol in Caracas.
A demonstrator holds a banner that reads, "Maduro Out."
Venezuelan opposition activists organize a sit-in to block the Francisco Fajardo motorway in Caracas.
An opposition activist marches against Venezuelan President Nicolas Maduro.