Venezuelan police have clashed with demonstrators protesting against a decision by Hugo Chavez's administration not to renew the free-to-air licence of Radio Caracas Television as thousands of Chavez supporters celebrated the opening of a government-run channel to replace the only opposition-aligned station with national reach.
Police said at least four officers were lightly injured after some protesters threw rocks and bottles, and they responded with water cannon.
RCTV is to go off the free airwaves at midnight (04:00 GMT), although it is allowed to continue transmitting via cable and satellite.
Opponents of the decision to curb its reach say Chavez is limiting freedom of expression.
Al Jazeera's Lucia Newman said Venezuelans had been urged to hold a "noise protest" with horns, pots and pans, and whistles at midnight to sound the alarm against what some see as the "silencing" of RCTV.
Gledys Ibarra, a soap opera actress, said: "What is happening here is simply the silencing of a television station."
The government says it is not renewing RCTV's licence after 53 years on air because it says the broadcaster participated in a failed 2002 coup against Chavez, incited violent demonstrations,
violated broadcast laws and showed excessive violence and sexual content.
Waving flags with the logo of RCTV, demonstrators packed the streets of the capital on Saturday where news anchors and soap opera stars criticised the decision not to renew the opposition channel's free-to-air licence.
Opposition voice
Critics condemned the decision for silencing an influential opposition voice and called the move evidence that Chavez's self-styled socialist revolution is concentrating power and muzzling the opposition.
Miguel Angel Rodriguez, RCTV journalist, told Al Jazeera: "Chavez is trying to show the world that here in Venezuela he can to whatever he pleases, and not only to the press, but to everybody that he wants to silence."
But RCTV's news director during the coup attempt told Al Jazeera that he believes that Chavez is doing the right thing.
"Destabilisation is when you broadcast military men dressed in military fatigues wearing ski masks and bearing weapons asking people to rebel against a democratically elected government," Andres Izarra, now head of the state sponsored network Telesur, said.
"That's a very clear case of destabilisation, not criticism."
RCTV said on Sunday that Venezuelan troops had taken over its transmission stations across the country, after a court order on Friday, in a show of force to prevent protests from turning violent.
RCTV said in a statement the court decision constituted a "kidnapping of equipment," but gave assurances it would stop broadcasting before midnight on Sunday in compliance with government orders.
President's warning
Chavez on Saturday reiterated warnings to his political foes not to foment violent demonstrations, following weeks of government accusations that opposition leaders were preparing to "destabilise" the government.
Chavez said: "If your even think of creating violence, you will regret it, gentlemen of the Venezuelan oligarchy and your masters in the North American empire."
Thousands of Chavez supporters dressed in their signature red T-shirts filled a Caracas avenue on Sunday to celebrate the opening of the new government-run channel that will replace RCTV on the free airwaves 15 minutes after its licence expires at midnight.
Late on Friday, a group of demonstrators shouting pro-Chavez slogans spray-painted the headquarters of Globovision, the country's last openly anti-government station, which Chavez has also threatened to take off the air for its critical coverage.
Most Venezuelans - 71 per cent according to a recent poll - oppose the restrictions on RCTV, and there has also been criticism from abroad, including a US senate resolution last week unanimously condemning "transgression of freedom of thought and expression" in Venezuela.