The US news channel CNN says it regrets a production mistake which Venezuelan President Hugo Chavez said could encourage attempts to assassinate him.
Mr Chavez has often accused the US of trying to assassinate him
On Tuesday, CNN's Spanish service showed a caption reading "Who killed him?" over a report about Mr Chavez and Colombian President Alvaro Uribe.
The caption - which was quickly removed - came from another story about the death of an American football star.
Mr Chavez has urged Venezuelan prosecutors to consider legal action.
He showed footage of the incident repeatedly during a two-hour appearance on the Venezuelan state television channel.
In a statement, CNN said its presenter had immediately made clear on air that there had been a mistake.
The channel said it would also broadcast further on-air clarifications of the incident.
It is not the first time Mr Chavez has attacked CNN, which he has accused of being involved in a campaign by Washington to destabilise Venezuela.
CNN denies that its reporting is biased and says it has no links to the US government.
Mr Chavez is campaigning for a referendum on Sunday on a series of constitutional reforms, which include a measure that would allow him to be re-elected indefinitely.
Opinion polls suggest it could be the closest contest Mr Chavez has faced since he became president in 1999.
In his television appearance, Mr Chavez warned of "destabilisation plans" and said that "a gang of fascists" must not stop "the march of history".
He said the security forces were ready and urged his supporters to turn out to vote in large numbers.
"We are going to win cleanly", Mr Chavez said.
University students are leading the opposition to the constitutional reform plans.
They accuse Mr Chavez of seeking to take away basic freedoms and trying to stay in power permanently.