By Diego Ore and Brian Ellsworth

CARACAS (Reuters) - Two Venezuelans died from gunshot wounds during protests against socialist President Nicolas Maduro, witnesses and local media said on Saturday, pushing the death toll from almost two months of anti-government demonstrations to 33.

Troops briefly clashed with a small group of protesters who attempted to block a highway in an upscale neighborhood of the capital after thousands of opposition sympathizers marched to demand the release of students imprisoned during the unrest.

Demonstrators complaining of soaring prices and product shortages have vowed to remain in the streets until Maduro resigns, although there are few signs that the country's worst turmoil in a decade will force him from office.

Argenis Hernandez, 26, was shot in the abdomen as he was demonstrating near a barricade in the central city of Valencia and died early on Saturday in a nearby hospital, according to local media reports.

A motorcyclist attempted to cross the barricade and opened fire on demonstrators when they would not let him through, wounding Hernandez.

Bus driver Wilfredo Rey, 31, died on Friday night after being shot in the head during a confrontation between demonstrators and hooded gunmen in the western city of San Cristobal, according to residents of the neighborhood where the incident took place.

Rey had not been involved in the protests, they said.

The protests began in February with sporadic demonstrations by university students. They intensified after three people were killed following a February 12 rally in downtown Caracas.

Jailed opposition leader Leopoldo Lopez called on Maduro to resign in a letter read out by his wife at a rally.

"Maduro, if you resign, you will open a path toward peace for Venezuelans," wrote Lopez, who was jailed last month on charges including instigating violence after helping turn the protests into a national movement. "The solution is in your hands."

A group of demonstrators later gathered near Plaza Altamira, which has been a hot-spot of opposition protests, but the National Guard dispersed them with tear gas.

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DUELLING MARCHES

The opposition has repeatedly declined Maduro's offers for dialogue about the situation, saying they refuse to take part in meetings that will provide little more than photo-ops for the ruling Socialist Party.

Maduro says their refusal to engage in dialogue is evidence they are interested in snatching power rather than negotiating.

During a rally following the pro-government march, Maduro accused opposition extremists of setting fire to a military university in San Cristobal earlier this week.

"Can this be called protest? This is terrorism, this is fascism," Maduro said.

"These 'Chuckies' are the direct descendants of the Nazis," he said, referring to the murderous doll of the horror movie series - a designation often used by government leaders to describe the violent protesters.

Demonstrations have ranged from peaceful marches to violent clashes between police and hooded protesters hurling rocks and Molotov cocktails.

They have also involved street barricades made of trash and debris that is set on fire, snarling traffic and angering drivers of all political persuasions.

Opposition sympathizers accuse troops of using excessive force against demonstrators, spurring outrage that has helped keep the protests going.

Maduro says adversaries are seeking to destabilize the government as part of a Washington-backed coup similar to the one that briefly ousted socialist leader Hugo Chavez in 2002.

Prosecutors in recent days ordered the arrest of two opposition mayors following accusations they had not done enough to clear barricades in their municipalities.

Congress on Tuesday asked prosecutors to open a criminal probe of Maria Corina Machado, an opposition legislator and high-profile protest leader, for crimes including treason and inciting civil war in association with the unrest.

(Additional reporting by Javier Faria in San Cristobal; editing by Gunna Dickson)