The attorney general's office said gunmen were alleged to have opened fire Saturday on an anti-government demonstration in the western city of Valera.
"At that moment, (Edy Alejandro) received a bullet in the chest," it said in a statement.
Also wounded in the shootings were an 18-year-old male and a 50-year-old woman, it said. Teran was 23.
The incident came amid massive demonstrations across the country on Saturday demanding elections to replace Maduro.
In some cities, the protests degenerated into violent clashes between demonstrators and police and government troops.
In Caracas, the mayor of a municipality in the eastern part of the city said 46 people were injured, and in the suburb of San Antonio Los Altos a youth was wounded by gunfire, the opposition governor of the state of Miranda said.
Since the protests began April 1, hundreds of people have been injured and some 2,200 have been detained, 161 of them jailed on orders of military courts, Foro Penal, a non-governmental monitor, said.
Seven in 10 Venezuelans reject Maduro's leadership, according to private surveys, amid widespread economic devastation aggravated by the drop in the prices of oil -- Venezuela's chief revenue source -- in 2014.
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