The ex-wife of Venezuelan President Hugo Chavez has apologized for once playing a role in her former husband's political agenda.

"[My words] have a deep sense of apology, because I recognize that I'm in part a bit responsible for the situation today," said Maria Isabel Rodriguez during a news conference Tuesday in Barquisimeto.

"I'm not directly responsible for the things happening in the country, but I have to recognize that at some point I was part of this [government] and I want to apologize."

Her comments come days before Venezuelans vote in a referendum on constitutional changes giving the president the right to run for office indefinitely, increase presidential terms from six to seven years and push the country toward further socialist reforms.

Rodriguez, one of Chavez's two ex-wives, warned voters against the proposals.

"Any constitution that defines itself as good or ideal, has first to guarantee all human rights, but with this reform even the right to life is at risk," Rodriguez told reporters.

Polls suggest voters are equally split on support for the reforms.

About 300 anti-Chavez supporters demonstrated in Caracas on Wednesday, holding signs calling on people to vote No on Sunday. As well, several hundred pro-and anti-referendum demonstrators clashed in Puerto La Cruz, a city about 240 kilometres east of the capital.

Also Tuesday, Chavez warned his opponents that if the opposition uses violence in opposing his reforms, he will launch a counterattack.

"If you launch a violent attack, you can be sure that I am going to counterattack, and I will remove the space that those bastard opponents still have," Chavez said, speaking on a TV show.

Wants probe into CNN

Chavez on Wednesday accused U.S. television news network CNN of attempting to instigate his murder by showing a photo of him with a caption that read, "Who killed him?"

The caption appeared to be a production mix-up with another item about the death of an NFL player.

Chavez, however, who made the allegations on state television, questioned why the caption remained on screen for several seconds.

"I want the state prosecutor to look into bringing a suit against CNN for instigating murder in Venezuela," he said. "Undoubtedly it is part of the psychological warfare."

The outspoken Chavez recently called former Spanish Prime Minister Jose Maria Aznar a fascist at a regional summit —prompting the country's king Juan Carlos to tell him to "shut up" — and announced he was freezing ties with Colombia following a spat with his Colombian counterpart Alvaro Uribe.

Chavez said he would cut off relations with the Colombian government so long as it was headed by Uribe, saying he could not have a relationship with a president who "disrespects another president that he has called a friend."

The two South American leaders have been in a spat since Uribe abruptly ended Chavez's mediation last week between the Colombian government and rebels.

Chavez has also called senior members of Venezuela's Roman Catholic Church "dolts and mental retards," and last year referred to U.S. President George W. Bush as the "devil" during a United Nations summit.

With files to the Associated Press