By Daniel Wallis and Diego Ore
CARACAS (Reuters) - At least two people were shot dead on Wednesday during anti-government protests in Caracas, escalating the worst bout of unrest in Venezuela since turmoil after President Nicolas Maduro's election last year.
The deaths illustrated the South American OPEC nation's deep political divide and volatility almost a year after the death of former socialist leader Hugo Chavez.
Government officials said a Maduro supporter and one other person were killed amid chaotic scenes as a march against Maduro's government and a rally to support the president ended just a few blocks apart in the city center.
"He was a comrade assassinated by the right-wing fascist hordes," National Assembly President Diosdado Cabello said of the first victim, a community leader from a poor neighborhood.
With both sides blaming each other for the violence, the opposition said two student protesters had died, but there was no official confirmation.
"We have two Venezuelans killed for raising their voices," opposition leader Maria Corina Machado said.
Reuters reporters on the scene heard gunshots and saw one man carried away dead with blood gushing from his head.
Twenty-three people were injured, 25 arrested, four police vehicles burnt, and some government offices vandalized in violence throughout the day, officials said.
As night fell, soldiers fired tear gas at several hundred young demonstrators who burned tires and blocked the main avenue of the upscale district of Chacao.
Under the banner "The Exit," meaning Maduro's departure, hardline opposition groups have been holding mostly small protests around the country for the last two weeks, to complain about rampant crime, corruption and economic hardships.
Some have degenerated into rock-throwing skirmishes with security forces in the first sustained trouble since last year's post-election riots that killed half a dozen people.
"We're staying in the streets until this government falls," said student Jose Jimenez, 22, protesting in Chacao with a shirt tied round his face to protect him from tear gas.
Maduro, a 51-year-old former bus driver and union activist who has pinned his presidency on maintaining the legacy of late socialist leader Hugo Chavez, says right-wing "fascists" are seeking to destabilize his government and topple him.
"A Nazi-fascist current has emerged again in Venezuela, they want to lead our nation to violence and chaos," Maduro told pro-government demonstrators clad in the red colors of the ruling Socialist Party at their rally before the violence broke out.
A few blocks away, thousands of opposition supporters had gathered in a square and marched toward some government buildings, chanting and blowing horns and whistles.
"We don't want a Cuban dictatorship," some chanted, in a reference to accusations that Maduro is a stooge of Cuba's President Raul Castro and his brother Fidel.
"You need therapy to live in Venezuela!" read one banner, held up by members of a university psychology department.
The marches were held as part of Wednesday's "Youth Day" commemoration that celebrates the participation of students in a 19th century independence battle against colonial authorities.
About 45 demonstrators have been arrested since two hardline opposition groups began calling for street protests two weeks ago to try to force Maduro to resign.
Opposition activists said armed pro-government supporters belonging to "colectivos" attacked and shot at people protesting in the western Andean city of Merida on Tuesday, injuring five.
"They were attacked by the colectivos while exercising their right to peaceful protest," said Tamara Suju, who is tracking the violence for one of the parties, Popular Will.
Maduro blamed the Merida incident on opposition provocateurs posing as Socialist Party sympathizers.
"They cannot take us back to the scenes of 2002," Maduro said in a reference to massive street protests that culminated in a brief, military-led coup against Chavez.
Some student protesters in the state of Merida have thrown rocks and blocked roads. Police officers have been injured during student-led protests in another western state, Tachira.
The current protests have been much smaller than the 2002 wave. Many in the opposition favor a more moderate approach.
"While there are plenty of reasons to protest, there does not seem to be an agenda for the current wave. #LaSalida (The Exit) is not a strategy. It's a hashtag!" complained the anti-government blog Caracas Chronicles.
"The street protests, along with the public bickering they are engendering, are creating a false sense that our actions can undo the regime, while at the same time casting doubt on the opposition's unity."
(Additional reporting by Caracas bureau reporters; Writing by Andrew Cawthorne; Editing by Brian Ellsworth, Kieran Murray and Lisa Shumaker)