Masked youths at the head of a Venezuelan opposition march on Wednesday lit fires and hurled stones at security forces who shot teargas to stop their latest demonstration against President Nicolas Maduro.
Protesters were enraged by the socialist president launching procedures with the electoral council to draw up a new constitution.
In a familiar pattern from a month of protests against the socialist government, thousands of opposition supporters rallied peacefully for several hours before being blocked, sparking fights between youths and National Guard troops.
At least 33 people have been killed and hundreds injured and arrested since the anti-Maduro unrest began in early April.
TRT World spoke to Caracas-based journalist Juan Lamas for the latest update.
The marchers tried to reach the National Assembly legislature, where the opposition has a majority, to protest Maduro's creation of an alternative "popular" congress viewed by foes as a ruse to dodge free elections and cling to power.
They were blocked by National Guard forces with teargas, armoured vehicles and riot shields on the Francisco Fajardo highway, which runs through the middle of the city.
On the opposition side, youths donned gas masks and bandanas, throwing Molotov cocktails and using slingshots to fire stones.
They protected themselves with homemade shields, painted in bright colors and decorated with slogans like "Liberty!" and "Murderer Maduro!"
Opposition leaders have vowed to stay in the streets after Maduro's announcement on Monday that he was creating a "constituent assembly" empowered to rewrite the constitution.
The opposition, however, says Maduro's use of a "constituent assembly" is a cynical ploy to confuse citizens into thinking he has made concessions when in fact he is seeking to tweak the system to avoid elections the Socialist Party would likely lose.
Maduro's move has drawn condemnation from the United States and some Latin American countries, including regional powerhouse Brazil that labelled it a "coup."
But backing has come from regional leftist allies including Cuba. Bolivia's President Evo Morales said Venezuela had the right to "decide its future... without external intervention."