A 20-year-old Venezuelan protester died on Friday after being shot in the head, authorities said, taking fatalities from a month of anti-government unrest to at least 37 as the opposition geared up for more demonstrations.

Hecder Lugo was hurt during fighting between demonstrators and security forces in Valencia on Thursday that also injured four others, the local opposition Mayor Enzo Scarano said in a series of tweets.

The state prosecutor's office, which keeps an official count of deaths since protests began against socialist President Nicolas Maduro in early April, confirmed he died after being shot in a protest.

Another 717 people have been injured and 152 are still in jail from the hundreds rounded up in widespread unrest around the volatile South American OPEC nation of 30 million people, according to the office's latest tally.

There has been violence and widespread looting this week in Valencia, a once-bustling industrial hub two hours from the capital by road.

And in an incident loaded with symbolism, a handful of young men destroyed a statue of late leader Hugo Chavez in the oil-producing Zulia state, according to videos circulating on social media on Friday evening.

Footage shows the statue, which depicts Chavez saluting and wearing a sash, being yanked down to cheers in a public plaza before it is bashed into a sidewalk and then the road as onlookers swear at the leftist, who died in 2013 from cancer.

A group of protesters run during clashes in Barquisimeto, Venezuela on 5 May (EPA)

"Students destroyed this statue of Chavez. They accuse him, correctly, of destroying their future," opposition lawmaker Carlos Valero said about the incident, which was also reported in local media. Reuters was unable to independently confirm it.

Venezuela's opposition, which now enjoys majority support after being in the shadow of the ruling Socialist party since Chavez's 1998 election win, says his successor Maduro has become a dictator and wrecked the economy.

Vowing to stay in the streets for as long as necessary, opposition leaders announced nationwide women's marches for Saturday with the biggest planned for the capital Caracas.

Opposition lawmakers briefly unfurled a banner on Friday at the National Assembly, where they won a majority in 2015 thanks to voter ire over the recession, saying "Maduro Dictator".

The president says they are seeking a violent coup with U.S. support, and is setting up a "constituent assembly" super body to shake up public powers, change the constitution, and possibly replace the existing legislature.

"President Maduro has made a big call to national dialogue," Foreign Minister Delcy Rodriguez told diplomats at a meeting on Friday, showing them images of violence and vandalism on the streets caused by youths at the front of protests.

"They are not peaceful, the opposition leaders share big responsibility in these acts of extremism and vandalism."

Opposition protests have often started peacefully but degenerated into violence when security forces block marchers and masked youths fight them with stones, Molotov cocktails and fireworks shot from pipes turned into homemade mortars.

In pictures: The crisis in Venezuela Show all 22 1 /22 In pictures: The crisis in Venezuela In pictures: The crisis in Venezuela A girl scavanges for food in the streets of Caracas Getty Images In pictures: The crisis in Venezuela A man scavenges for food next to girls in the streets of Caracas. Venezuelan President Nicolas Maduro is resisting opposition efforts to hold a vote on removing him from office. The opposition blames him for an economic crisis that has caused food shortages Getty Images In pictures: The crisis in Venezuela Venezuelans line up to get the 'Fatherland's Card' at Bolivar Square in Caracas Getty Images In pictures: The crisis in Venezuela The mother of Venezuelan Rebecca Leon, who scavenges for food in the streets of Caracas, feeds her grandson at their house in Petare shantytown. Getty Images In pictures: The crisis in Venezuela Venezuelan Rebecca Leon, who scavenges for food in the streets of Caracas, with her two-year-old son at her house in Petare shantytown Getty Images In pictures: The crisis in Venezuela Members of a pro-government community organisation work in an expropriated bakery in Caracas. Supported by popular militiamen, Venezuelan government inspectors oversee bakeries as bread comes out of the oven, to undermine an alleged plot to induce scarcity of this staple food Getty Images In pictures: The crisis in Venezuela Forensic police stand next to the body of a man outside a supermarket, where he died of a heart attack after waiting in a long line to buy food, in Caracas Getty Images In pictures: The crisis in Venezuela Venezuelan opposition activists take part in a protest against the government of President Nicolas Maduro at the Francisco Fajardo highway in Caracas Getty Images In pictures: The crisis in Venezuela National guard throws a tear gas canister during a rally against Venezuela's President Nicolas Maduro's government in Caracas, Venezuela Reuters In pictures: The crisis in Venezuela Opposition supporter shouts at a police officer during a rally against Venezuela's President Nicolas Maduro's government in Caracas Reuters In pictures: The crisis in Venezuela Opposition supporters clash with national guards during a rally against Venezuela's President Nicolas Maduro's government in Caracas Reuters In pictures: The crisis in Venezuela A boy wearing a t-shirt with the colours of the Venezuelan national flag, during a demonstration against President Nicolas Maduro's government at Foreign Affairs Ministery, in Buenos Aires, Argentina AP In pictures: The crisis in Venezuela Protesters cover themselves from tear gas fired by the Venezuelan National Guard officers during a protest in Caracas AP In pictures: The crisis in Venezuela Opposition supporters clash with national guards during a rally against Venezuela's President Nicolas Maduro's government in Caracas Reuters In pictures: The crisis in Venezuela Venezuelan opposition activists take part in a protest -blocked by the National Guard- against the government of President Nicolas Maduro at the Francisco Fajardo highway in Caracas Getty Images In pictures: The crisis in Venezuela A Venezuelan national guard reacts to the effect of pepper spray during a protest of opposition supporters against Venezuela's President Nicolas Maduro's government in Caracas Reuters In pictures: The crisis in Venezuela Opposition supporters holding a Venezuelan flag protest against Venezuela's President Nicolas Maduro's government during a rally in Caracas Reuters In pictures: The crisis in Venezuela Opposition supporters clash with riot police during a protest against Venezuela's President Nicolas Maduro's government in Caracas, Venezuela Reuters In pictures: The crisis in Venezuela Opposition supporters protest against Venezuela's President Nicolas Maduro's government during a rally in Caracas Reuters In pictures: The crisis in Venezuela Venezuela's Supreme Court abandoned measures to seize power from the opposition-controlled legislature after the moves drew international condemnation and raised pressure on President Nicolas Maduro. The president of Venezuela's National Assembly Julio Borges dismissed the court's gesture and told reporters that nothing had changed and the coup continued Getty Images In pictures: The crisis in Venezuela Venezuelans living in Peru and other protesters take part in a rally against Venezuelan President Nicolas Maduro's government, outside the Venezuela embassy in Lima, Peru Reuters In pictures: The crisis in Venezuela Venezuelans living in Peru and other protesters take part in a rally against Venezuelan President Nicolas Maduro's government, outside the Venezuela embassy in Lima, Peru Reuters

Fatalities have included supporters of both sides, bystanders and members of the security forces.

Gunshot wounds have been the most common cause of deaths.

The opposition is boycotting Maduro's constituent assembly process, saying it is a ploy to keep him in power by setting up a body with mechanisms to ensure a government majority.

Having failed to trigger a referendum on his rule last year, the opposition is calling for delayed state gubernatorial elections to be held as soon as possible, and for the next presidential election slated for 2018 to be brought forward.

Polls show the ruling Socialists would badly lose any conventional vote due to four years of economic crisis that has led to debilitating food and medicine shortages.

While Maduro says opposition ranks include armed hoodlums, activists accuse the security forces of using excessive force including firing tear gas canisters directly at people and allowing pro-government gangs to terrorise demonstrators.

Opposition leader Henrique Capriles said on Friday that 85 members of the military in Caracas had been arrested for opposition "repression," adding that their relatives had asked him to publicise the detentions.

"Cousin, it's enough!" Defence Minister Vladimir Padrino's cousin, Ernesto Padrino, wrote to him in an open letter.

He was following in the footsteps of the state human rights ombudsman's son who surprised the country by publishing a video begging his father to "end the injustice."

"Eighty percent of Venezuelans want elections as a way out of our nation's grave economic and political crisis," wrote Ernesto Padrino on Facebook.

"Sooner or later, the Venezuelan people will make you pay."