Three more people have been killed in Venezuela, in rival protests both for and against the government of President Nicolas Maduro.
The latest violence raised the death toll to 24 in three weeks of protests.
Public defender Tarek Saab said several others were seriously injured and "between life and death".
The latest protests were sparked by the decision of the Supreme Court to take over the powers of the opposition-dominated National Assembly.
The court's reversal of the ruling was not enough to stop a wave of demonstrations, with opposition supporters calling for immediate elections.
On Monday a man was shot dead in a pro-government demonstration in the city of Merida. Two other men - one in Merida and another in the nearby town of Barinas - also died, though it is not clear what side of the protests they were on.
Merida state governor Henrique Capriles, one of Venezuela's main opposition leaders, tweeted that "paramilitary groups" were responsible for the killings.
Twelve people have been killed in pro and anti-government demonstrations this month so far.
Another 11 people died on Friday when a bakery was looted in Caracas.
Monday's protest was labelled a "national sit-in" by the opposition, blocking the main roads in the country.
The scene in Caracas: Daniel Pardo, BBC
Little by little the Caracas highway, a huge avenue that crosses the capital, was filled with people dressed in white.
Some brought board games, others carried food and drinks. And some brought vinegar and baking soda in case the protest was dispersed with tear gas.
Like the silent protest on Saturday, this a creative attempt to refresh the forms of protest that have been repressed, or have become predictable.
By blocking Caracas, the opposition has achieved its first goal of calling attention.
But the opposition spokesmen, mounted on trucks, said the end goal is clear: elections.
Demonstrators who spoke to the BBC, however, just hope that there will be a change of direction: renewal of public powers, release of imprisoned politicians - any change, at this stage, will be welcome.
There have been anti-government protests across cities in Venezuela almost daily this month, while government supporters have been holding marches to show their loyalty to President Maduro.
Both government and opposition supporters as well as bystanders have been killed.
There is little sign of the protests subsiding as the opposition has vowed to "stay on the streets" until presidential elections due to be held at the end of 2018 are brought forward.
Vatican-backed talks held late last year failed to yield any notable agreements and ended after the opposition accused the government of intransigence.
Opposition groups have called on their supporters to hold another protest on Wednesday.
List of people killed in marches and unrest since 1 April:
- Jairo Ortiz, 19, killed on 6 April in Miranda state. According to Venezuela's Interior Ministry, Mr Ortiz was not taking part in anti-government protests when he was shot dead. A police officer has been arrested in connection with the shooting.
- Daniel Queliz, 20, killed on 10 April in Valencia state. Shot in the neck during an anti-government protest.
- Brayan Principal, 14, killed on 11 April in Lara state. Shot in the abdomen during anti-government protests in the city of Barquisimeto.
- Miguel Ángel Colmenares, 36, killed on 12 April in Lara state. Shot 11 times, witnesses said he was targeted by "colectivos", pro-government militant grassroots groups.
- Gruseny Antonio Canelón, 32, died on 13 April after being shot during a anti-government protests in Lara state.
- Carlos José Moreno, 17, shot in the head on 19 April in the centre of Caracas near an opposition demonstration. Was on his way to play football, his brother said.
- Paola Ramírez, 23, shot on 19 April near an anti-government demonstration in Táchira state. Witnesses said "colectivos" were to blame, while the interior minister blamed an opposition party.
- Neomar San Clemente, 28, sergeant in the National Guard, officials said he was killed by a "sharpshooter" during an anti-government protest near Caracas on 19 April.
- Melvin Fernando Guittian, 26, shot in the stomach as he was returning to his home amid anti-government protests on 20 April.
- Almelina Carrillo, 47, died on 23 April after being hit by a bottle of frozen water during a pro-government march on 19 April in Caracas.
- Jesus Sulbaran, 42, shot in the neck during protests in Merida on Monday 24 April.
- Renzo Rodríguez Roda, 54, shot in the chest during demonstrations in Barinas on 24 April.
- Eleven people died in the El Valle area of Caracas between Thursday 20 and Friday 21 April, many of them were electrocuted when a bakery was looted.