Updated

The countdown has begun for Venezuela's oldest private television station. At midnight Sunday, Radio Caracas Television — the most widely watched channel — will be forced off the air after President Hugo Chavez's government decided not to renew its license.

Talk show host Miguel Angel Rodriguez, whose program is a daily rant against Chavez, ended his Friday segment by blowing a kiss to the camera and saying defiantly: "There is no goodbye. It's 'see you later."'

The opposition plans street protests over the weekend to demand that RCTV be allowed to keep transmitting, while Chavez supporters are expected to hold their own demonstrations. The authorities tightened security Friday in Caracas, putting hundreds of police and National Guard troops along major avenues.

Hundreds of university students chanted "No to the closing!" as they gathered in Caracas Friday for a march to Venezolana de Television — the main state-run channel. They said they were going to demand to use the state-run airwaves to criticize the RCTV decision.

"People have to realize that we have a totalitarian president," said Maria Alecia Klemprer, a 25-year-old university student wearing a T-shirt reading: "Freedom of Expression S.O.S."

Chavez defends the decision as a legal move to democratize the airwaves by reassigning RCTV's license to a public service channel. The government provided startup funding for the new channel, TVES, and says it will start broadcasting early Monday in some parts of the country.

In a speech on Friday that Venezuela's private TV channels were obliged to broadcast, Chavez rejected allegations that his decision threatened freedom of expression.

"There's no country in the world where there is so much freedom of expression," he said. "The license expires at midnight on May 27, and it's not going to be renewed."

Inside the studios of RCTV, meanwhile, the mood was somber yet defiant, with some employees wearing T-shirts reading "No to the closing."

"There is a lot of uncertainty. It's very hard," said technician and 22-year RCTV veteran Alejandro Gonzalez Natera, who wiped away tears as he spoke.

At least some of the station's roughly 2,500 employees will stay on, producing soap operas that are watched on other stations throughout Latin America.

RCTV was founded in 1953 and broadcasts a mix of talk shows, sports, locally produced soap operas and an immensely popular comedy program called "Radio Rochela," which often pokes fun at Chavez. RCTV has regularly been the top channel in viewer ratings.

Groups such as Human Rights Watch and Reporters Without Borders have called the government's move a flagrant effort to silence criticism, and the Senate Foreign Relations Committee on Thursday passed a resolution condemning it. It was sponsored by Republican Dick Lugar had bipartisan support, including from Democrats Hillary Clinton and Barack Obama.

Chavez said the fact that only 65 of the European Parliament's 785 members participated in a vote condemning the government's decision showed the issue was of little interest, and added that Venezuela's "oligarchy has lost some money" lobbying for that resolution.

Chavez accuses RCTV and other opposition-aligned private media of supporting a failed 2002 coup against him. The channel has been accused of violating broadcast laws and showing programs with violence and sexual content that are morally degrading.

RCTV's general manager, Marcel Granier, challenged the government's decision, but Venezuela's Supreme Court dismissed one legal challenge and declined to intervene in another, even as it has agreed to keep considering RCTV's appeal.

While many Venezuelan journalists have taken to the streets in protest, others have sided with the government.

Eleazar Diaz Rangel, editor of the newspaper Ultimas Noticias, argued that the "immense majority" of media organizations openly oppose the government.

On television, however, pro-government channels are dominant. Aside from RCTV, Globovision is the only other major opposition-aligned channel, and it is not seen in all parts of the country. Two other channels that used to be staunchly anti-Chavez, Venevision and Televen, have recently toned down their coverage.