CARACAS, Venezuela:Student protesters marching to protest against what they perceive as bias by Venezuela's electoral council clashed on Thursday with supporters of the late President Hugo Chavez.

"We are here to demand fair and clean elections," said Juan Urdaneta, a student leader who traveled hundreds of miles (kilometers) from the western state of Zulia to participate in the demonstration.

The protesters marched behind a sound truck playing the national anthem into downtown Caracas, chanting and blowing plastic horns.

Police in riot gear blocked off the avenue leading to the National Electoral Council in downtown Caracas. About 100 government supporters quickly gathered and began throwing rocks and bottles at the students.

Police attempted to separate the rival groups, but scuffles soon broke out and some students tossed objects back at government supporters, prompting security forces to fire tear gas canisters and shoot plastic bullets at aggressive Chavistas.

It was unclear how many people had been injured, but student leader activist Francisco Rodriguez said at least 10 people from his side had been hurt, most of them hit with rocks.

Splinter groups of Chavez supporters tried to attack the students from side streets, but were repelled by police.

Most of the students scattered and fled. But at one point, about 100 students were trapped by Chavistas who had blocked all the surrounding streets, preventing them from immediately leaving.

"The government supporters have ambushed us," student leader Vilcar Fernandez told The Associated Press. "There wasn't any protection on the part of the security forces."

The students were demanding the electoral council eliminate requirements that voters have their fingerprints recorded before voting and that it prevent the government from seizing television and radio airwaves at will to allow acting president Nicolas Maduro to promote his candidacy.

They were also demanding that Defense Minister Diego Molero, who has publicly voiced his support for Maduro, to step down from his post.

The constitution forbids the military from taking sides in politics, although soldiers are permitted to vote.

Maduro is competing against opposition leader Henrique Capriles, who has strongly criticized the electoral council for failing to stop government institutions from promoting Maduro's candidacy ahead of the crucial April 14 vote.

"It's not fair that the National Electoral Council allow such privileges for Maduro," complained Enzo Colaicoro, a student activist.