Thousands massed on highways in Caracas and other cities, promising to not budge for the promised 12 hours as they hoped to pile pressure on the unpopular government to quit and call for fresh elections.
Venezuelans launched the seventh week of anti-government demonstrations by blocking roads on Monday, vowing not to budge all day in protest against a deadly political and economic crisis. Their demands? President Nicolas Maduro's resignation and fresh elections.
Demonstrators have been on the streets daily since early April to demand elections, freedom for jailed activists, foreign humanitarian aid to offset an economic crisis, and autonomy for the opposition-controlled legislature. Clashes have left 38 people dead in protests against moves to strengthen Maduro's hold on power and his refusal to hold early elections.
Maduro accuses them of seeking a violent coup. The centre-right opposition accuses Maduro of taking the country into an economic crisis that has caused severe shortages of food and medicine.
Trying to vary tactics and keep momentum, protesters rode horses through Caracas on Saturday and took letters and flowers to police and military posts on Mother's Day on Sunday.
On Monday, thousands massed from 7 am local time on highways in Caracas and elsewhere, chanting slogans, waving banners, playing cards in deck chairs, enjoying impromptu sports games and sharing food.
"I'm here for the full 12 hours. And I'll be back every day there's a protest, for as long as is necessary," said Anelin Rojas, a 30-year-old human resources worker, sitting cross-legged with a novel and earphones in the middle of Caracas' main highway.
"Unfortunately, we are up against a dictatorship. Nothing is going to change unless we force them," Rojas added, surrounded by placards saying "Resistance!" and "Maduro, Your Time Is Up!"
A senior opposition lawmaker, Freddy Guevara, told reporters Monday's rally would go on for 12 hours until 2300 GMT.
He said 50 other similar "sit-ins" were planned on roads across the country with the aim of generating a state of "ungovernability" to pressure Maduro.
"This is a day of resistance, of endurance, of showing that we are organised and firm," Guevara said at the rally.
Using branches, rocks and garbage, demonstrators blocked the main Francisco Fajardo thoroughfare in Caracas from after dawn.
In western Tachira state, some farmers were striking in solidarity with the protesters. They gave away milk and cheese so it would not go to waste, witnesses said.
On Margarita island, opposition lawmaker Yanet Fermin was detained while mediating between security forces and protesters, her party said.
The opposition, which commands majority support after years in the shadow of the ruling socialists, is more united than during the last wave of anti-Maduro protests in 2014.
But the opposition has been unable to stop violence in its ranks, with youths hurling stones and petrol bombs, vandalising property and starting fires when security forces block the marches with tear gas, pepper spray and water cannons.
The current wave of protests, which has attracted hundreds of thousands of demonstrators on some days, has drawn greater support from the poor, who backed late leader Hugo Chavez massively. This demographic has soured on Maduro, his successor, and suffered the most from four years of recession.
But the main protests have still been in middle-class areas.
Maduro, 54, who narrowly won the election in 2013 after Chavez's death, says he is the victim of an international right-wing conspiracy that has already brought down leftist governments in Brazil, Argentina and Peru in recent years.