CARACAS A 17-year-old Venezuelan protester died in ferocious clashes between security forces and protesters in Caracas on Wednesday, taking the death toll from unrest since April to at least 66.
The government said Neomar Lander died when a homemade mortar exploded in his hands while hundreds of youths faced off with National Guard troops in the Venezuelan capital.
Opposition lawmakers, however, said he was killed by a tear gas cannister fired straight at him. The state prosecutor's office announced a probe, without giving details.
A Reuters photographer saw a young man, assumed to be Lander, lying bloodied and motionless on the street, receiving emergency first aid.
At least 66 people have died, with victims including government and opposition supporters, bystanders and members of the security forces, since demonstrations began against President Nicolas Maduro more than two months ago.
Each side blames the other for the violence.
Critics denounce Maduro as a repressive dictator, and are demanding general elections, foreign humanitarian aid, freedom for hundreds of jailed activists, and autonomy for the opposition-controlled National Assembly.
"We mustn't let fear intimidate us, let's stay in the streets to fight for all Venezuelans' future," said opposition lawmaker Miguel Pizarro, weeping at a news conference as he described seeing Lander's death.
"Soon we will able to say these were the last, dark days of the dicatorship."
Maduro, 54, calls his foes violent right-wing "fascist" conspirators seeking a coup similar to the short-lived 2002 toppling of his predecessor Hugo Chavez.
"This is criminal terrorism, and we must reject it," Maduro told supporters in a speech carried on state TV, comparing his foes to Adolf Hitler, Benito Mussolini and Augusto Pinochet.
In the worst turmoil of Maduro's turbulent four-year rule, thousands of people have been injured and arrested in recent weeks. Protesters are also complaining about hunger and shortages during a brutal economic crisis in the OPEC nation.
In Caracas on Wednesday, security forces using armored vehicles, water cannons and tear gas blocked opposition supporters from marching to the national election board's headquarters, sparking clashes around the city.
Masked youths with homemade shields hurled stones and Molotov cocktails, and set up burning roadblocks, while businesses and schools closed, and residents ran for cover.
Among hundreds of injuries reported in Caracas and other cities, the government highlighted the case of two National Guard soldiers wounded by gunshots when they were clearing a barricade in the El Paraiso district of the capital.
Seeking to keep the pressure on Maduro, the opposition announced further upcoming activities including a planned censure vote against the interior minister in the National Assembly and a rally in honor of Lander on Thursday.
Maduro has sought to take the heat out of the situation by announcing the creation of a super-body called a constituent assembly with powers to rewrite the constitution, but foes say that is a sham purely designed to keep the socialists in power.
The national election board announced on Wednesday that votes for the new assembly would still go ahead on July 30, despite an opposition boycott, criticism from some within government, and a legal appeal by state prosecutor Luisa Ortega who said it threatened to "eliminate" democracy.
The pro-government Supreme Court rejected her petition in a ruling made public on Wednesday.
(Additional reporting by Carlos Rawlins and Eyanir Chinea; Editing by Phil Berlowitz and Andrew Hay)