"If we don't do it now, then when? And if it's not us, who will?" he said.
The crowd then marched to the federal prosecutor's office to demand the release of 13 demonstrators who human rights groups say were illegally arrested during the past two weeks of protests.
A smaller group of mostly students lingered after most demonstrators went home, setting fire to trash and ripping apart concrete sidewalks and steel grating to throw at police and national guardsmen, who responded by firing rubber bullets into the air.
Almost none of the scenes of violence were broadcast on local television, which is dominated by state-run channels and private networks reluctant to criticize the government, leaving Venezuelans to turn to social media to stay informed.
International media outlets also faced obstacles. Colombia's NTN24 was providing live coverage but it was pulled from pay TV without explanation. Correspondents for The Associated Press and other media organizations were roughed up by police who smashed or seized their cameras.
Associated Press writers Fabiola Sanchez, Ricardo Nunez and Jorge Rueda contributed to this report.
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