RCTV's imminent closure drew thousands onto the streets

The head of the RCTV station addressed the marchers, urging them to defend freedom and "free independent media".

President Chavez has said he will not renew a licence for the RCTV network which is due to expire on 27 May.

He accuses the opposition-allied TV station of supporting a failed coup against him in 2002.

He has referred to opposition television stations in general as "horsemen of the apocalypse" and has blamed RCTV in particular for spreading immorality with its steamy soap operas.

Mr Chavez plans to replace RCTV with a government-funded TV station.

Bolivar citation

Marcel Garnier, RCTV's managing director, told a crowd of cheering protesters in Caracas that Mr Chavez was trying to "topple the country over the precipice of totalitarianism where not even his own supporters can express their opinions".

He said the president should pay more attention to the words of Simon Bolivar, a hero of Mr Chavez famed for leading South Americans in the fight against colonialism.

"He who rules must listen, the people are speaking," Mr Garnier said, quoting Bolivar.

President Chavez was re-elected by a landslide last year.

His welfare spending programme has won him massive support among the poor but his opponents accuse him of turning the country into an increasingly authoritarian socialist state, modelled on Fidel Castro's Cuba.