Venezuela's opposition renewed nationwide protests on Thursday to pressure the government of President Nicolas Maduro to hold elections and improve a collapsing economy, a day after three people were killed in similar demonstrations.

However, crowds were smaller than the hundreds of thousands of people who flooded the streets of Caracas and provincial cities on Wednesday, the latest and largest in several weeks of protests against what Maduro's opponents condemn as a lurch toward dictatorship.

Government officials dismiss the protests, characterized by street barricades and clashes with security forces, as violent and lawless efforts to overthrow Maduro's leftist government with the backing of ideological adversaries in Washington.

The opposition counters that Maduro, deeply unpopular as Venezuelans grapple with triple-digit inflation and shortages of food and basic consumer goods, is seeking to stay in power indefinitely by barring opposition leaders from office and quashing independent state institutions.

Naked protester

Tens of thousands of protesters have been on the streets of Venezuela's capital, but all eyes have focused on just one person — a young man who stripped down to his sneakers and walked naked through clouds of tear gas and lines of riot police.

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A naked demonstrator approached heavily armed police, holding out a Bible. His back was marked with bruises from rubber bullets. (Carlos Garcia Rawlins/Reuters)

A hush fell over a crowd of protesters who had shut down the main highway in Caracas when the lanky young man approached. Wearing just sneakers and tube socks, he approached heavily armed police in gas masks. There, he asked officers to allow the protesters to assemble peacefully, and held out a Bible.

The man's back was marked with bruises from rubber bullets. At one point, he climbed onto an armoured police vehicle and officers shouted for him to get down. But for the most part, he created a zone of calm amid another chaotic day of a now three-week-old protest movement. Police kept their distance, and protesters hushed when he passed.

Photos and videos of the man have flooded Venezuelan social media.

"It's time for the armed forces to realize that they're protecting corrupt leaders and not the Venezuelan people," said opposition lawmaker Jorge Millan, who represents part of the poor hilltop Caracas neighbourhood of 23 de Enero, once a government stronghold.

The opposition had called on its supporters to gather at about two dozen points around Caracas and march to the office of the state ombudsman, a human rights activist, just as they tried to do on Wednesday.

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Lilian Tintori, wife of jailed opposition leader Leopoldo Lopez, addresses supporters during the rally, part of a month-long protest effort during which eight people have been killed. (Christian Veron/Reuters)

The current wave of marches, the most sustained protests against Maduro since 2014, has sparked regular melees in which youths and National Guard troops exchange volleys of rocks and tear gas.

There were also late-night barricades and some looting in Caracas' middle class neighbourhood of El Paraiso on Wednesday night.

500 people arrested

Two students and a National Guard sergeant were killed in Wednesday's demonstrations, bringing the death toll in demonstrations this month to eight.

Rights group Penal Forum said more than 500 people were arrested in relation to Wednesday's protest and 334 remained in detention.

"We are concerned about the latest developments in Venezuela and urge that all efforts be made to lower tensions and prevent further clashes," a spokesman for UN Secretary-General Antonio Guterres said in a statement on Thursday.

Maduro, 54, called on his backers to stage counter-demonstrations in Caracas on Wednesday. Supporters of the president, who was elected in 2013 and assumed the socialist mantle of late leader Hugo Chavez, say the opposition's street protests are violent disruptions of public order that exceed the rights of free assembly and would not be tolerated in any other country.

'We've touched rock bottom'

The renewed wave of protests was sparked by a Supreme Court move in March to assume the powers of the opposition-led Congress, a move that it largely reversed a few days later.

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Demonstrators clash with riot police during a rally against Maduro, accused of supporting a Supreme Court ruling that suspended the opposition-majority National Assembly before the decision was reversed, amid food shortages and triple-digit inflation. (Carlos Garcia Rawlins/Reuters)

They were further fuelled when the government barred the opposition's best-known leader, two-time presidential candidate Henrique Capriles, from holding public office.

"This is the moment," said Raquel Belfort, a 42-year-old protester in wealthier eastern Caracas on Thursday, sporting a hat in the yellow, blue and red colours of the Venezuelan flag. "People are sick of this … we've touched rock bottom. I think if we take to the streets every day we'll end this government."

The push to keep up constant demonstrations increasingly mirrors protests in 2014 in which Maduro's critics barricaded streets and battled police for close to three months.

That effort ultimately faded amid protester fatigue and a heavy state crackdown. But the sharp deterioration of the economy, which has put many foods and medicines out of the reach of the average citizen, and a more organized and united opposition coalition have injected fresh energy into the current protests.

Maduro critics increasingly doubt that the ruling Socialist Party, which was soundly defeated in 2015 legislative elections, will allow for free and fair elections. The ballot for state governors has been delayed since last year and elections authorities have not announced when it will be held.

With files from The Associated Press