Scuffles then broke out before riot police intervened.
"I believe that the closing-down of the television station is very justified"
Medishagh, Nouakshott, Mauritania
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The latest protest came as a leading Chavez opponent demanded the release of almost 200 protesters jailed since Sunday.
Manuel Rosales, a former presidential candidate, said opposition to the government's move to halt the broadcasts of Radio Caracas Television (RCTV) showed that "freedom cannot be negotiated nor bargained".
In addition to free speech, he said protesters were demanding the right to protest "peacefully and democratically".
"Freedom for those young men and women, immediately. They should not be treated like criminals," said Rosales. "I know that Radio Caracas will return to the air."
Thousands have been converging at the capital's plazas and streets since Chavez took RCTV, the opposition-aligned channel and Venezuela's oldest station, off the air at midnight on Sunday.
He accused RCTV of inciting a coup attempt against him in 2002, a charge the station denied.
Police on Wednesday detained Oscar Perez, an opposition leader, as he was preparing another protest for the weekend.
Officials did not immediately comment on the arrest.
Since Sunday, more than 180 people, mostly university students and minors, have been detained, and at least 30 charged with violent acts.
It is unclear how many are still behind bars.
"We don't want a totalitarian country. We have the right to defend our freedom"
Virginia Montilla, protester
Chavez on Tuesday warned of a crackdown on another opposition-aligned television channel, Globovision.
Government officials claim Globovision encouraged an attempt on the president's life by airing the chorus of a salsa tune Have Faith, this Doesn't end Here, along with footage of the 1981 assassination attempt against Pope John Paul II.
Globovision dismissed the allegations as "ridiculous".
The station replayed footage of the assassination attempt during a retrospective of news events covered by RCTV during its 53 years in operation.
Separately on Wednesday, about 1,000 government opponents protested outside Venezuela's Air Force Command headquarters in the capital, banging on pots while shouting: "Soldiers, listen! Unite with the struggle!"
Virginia Montilla, 46, an office worker, said: "We don't want a totalitarian country. We have the right to defend our freedom."