By Deisy Buitrago
CARACAS (Reuters) - Police fired teargas on Thursday to control a flare-up in downtown Caracas between anti-government student protesters and supporters of the late President Hugo Chavez in an increasingly volatile atmosphere ahead of next month's election.
Several hundred students were marching to the election board's headquarters to demand a clean vote, when they were blocked by government supporters who hurled stones, bottles and eggs at them, a Reuters witness said.
"It's horrible, they're attacking us," said 19-year-old student Boris Walcheff.
Police fired three canister of gas towards the 150 or so government supporters and formed a cordon between the two sides. Some of the students also threw stones back, witnesses said.
It was the first outbreak of violence since an election was called on April 14 for the South American OPEC nation following Chavez's death from cancer two weeks ago.
Both candidates, acting President Nicolas Maduro and opposition leader Henrique Capriles, have been trading bitter personal accusations as they rally supporters for the vote.
Maduro, who is promising to continue Chavez's radical socialism in Venezuela, led two polls published this week by more than 14 percentage points.
Before the clash, the students had been marching to the election headquarters singing the national anthem and carrying signs including "Free and fair elections" and "Nicolas is a liar."
Government opponents say the election board and other institutions are biased. Officials deny that.
"We were holding a peaceful march," said another student, Carlos Vargas, 19, who was injured in the eye.
"Maduro sent these kids to stop us."
(Writing by Andrew Cawthorne; Editing by Daniel Wallis and Vicki Allen)