A nationwide strike against plans to rewrite the constitution shut down much of Venezuelan's capital before erupting into sporadic violence when protesters clashed with riot police and burned a post office near the headquarters of the main state-run broadcaster.
Wealthier, pro-opposition neighbourhoods of eastern Caracas were shuttered and silent until early afternoon, when improvised blockades left them almost entirely cut off from the rest of the city.
Groups of masked young men set fire to a handful of blockades and threw stones at riot police, who fired back tear gas.
A public transport strike appeared to have halted nearly all bus traffic and thousands of private businesses defied government demands to stay open as opponents of President Nicolas Maduro called the first major national strike since a 2002 stoppage that failed to topple Mr Maduro's predecessor Hugo Chavez.
Mr Maduro said on national television that he will press ahead with plans to rewrite the nation's constitution and said that hundreds of Venezuela's largest companies are functioning "at 100%" despite the strike. The claim could not be immediately confirmed.
In neighbourhoods of western Caracas traditionally loyal to the ruling party, some stores were closed but bakeries, fruit stands and other shops were open and hundreds of people were in the streets, although foot and vehicle traffic were about half of what they would be on a normal weekday.
In the rest of the city, residents commented that the streets were emptier than on a typical Sunday.
The 24-hour strike was meant as an expression of national disapproval of Mr Maduro's plan to convene a constitutional assembly that would reshape the Venezuelan system to consolidate the ruling party's power over the few institutions that remain outside its control.
The opposition is boycotting a July 30 election to select members of the assembly.
"Definitively, we need a change," said teacher Katherina Alvarez. "The main objective is for people to see how dissatisfied people are."
The country's largest business group, Fedecamaras, has cautiously avoided full endorsement of the strike, but its members have told employees that they will not be punished for coming to work.
Fedecamaras played a central role in the months-long 2002-2003 strike that Mr Chavez's political rivals and opponents in Venezuela's private business sector orchestrated in an attempt to topple him.
Mr Chavez emerged from the strike and exerted control over the private sector with years of expropriations, strict regulations and imports bought with oil money and meant to replace local production.
Business groups estimate that 150,000 Venezuelan businesses have closed over the last 15 years.
The opposition called a 12-hour national strike last year that saw little response and was widely seen as a failure.
The Venezuelan Workers' Confederation, a labour coalition with ties to the opposition, said at least 12 of its 20 member organisations across the country had decided to join the strike.
Transportation workers in the capital Caracas also said they would participate.
Many of those who opted to work said they walked hours to get to their jobs, unable to find a bus or taxi.
"We urgently need a change in government, because what we are living through is pathetic," said Frangeli Fernandez, 24, an accountant who walked three hours to his job at a bank.
Although not entirely in agreement with the strike, Mr Fernandez said he agreed with doing something "very radical to get out of this".
Walking through the streets of Venezuela's capital on Thursday, opposition leader Henrique Capriles called on people at roadblocks to allow ambulances and other emergency vehicles through.
Protesters across Caracas set up roadblocks of tree branches and tyres to protest against Mr Maduro's plans to change the constitution.
Some residents were irritated by the roadblocks, saying the protest was yet another way the country's political upheaval is disrupting their lives.
"The government jails the people who protest and those who are protesting are caging the rest of us. It's unfair," said Maria Sandoval, a 27-year-old medical secretary.
But those at the roadblocks said they had no plans to stop until Mr Maduro leaves power.
"The people don't want this government," accountant Wilfredo Villegas said as he manned a roadblock with neighbours.
"We're here making them understand that we don't want this government. They have to go, in a non-violent way. They have to call general elections."