"There is no possibility that Venezuela would turn him over to another country if Posada Carriles' extradition to Venezuela is approved," Vice President Jose Vicente Rangel said on Wednesday.
US authorities on Tuesday arrested 77-year-old Luis Posada Carriles, who entered the country in March and is wanted by Venezuela over the bombing of a Cuban airliner nearly 30 years ago.
"Today, US Immigration and Customs Enforcement took Luis Posada into custody, pending review of his immigration status," the Department of Homeland Security said in a statement, adding that it had 48 hours to decide on Posada's status.
Venezuela has demanded that Posada be extradited to face trial in the bombing, which left 73 people dead when the Cuban airliner exploded near Barbados after departing from Caracas.
"I think it's an excuse, a subterfuge, that they are using precisely in order to not approve the extradition," Rangel said.
"Bringing up that he could be sent to Cuba ... in this way they elude the commitment and the obligation they have to approve the extradition."
US officials have said they would not hand over those suspected of crimes to any country that would then turn them over to Fidel Castro's government.
Cuban President Castro holds the
US guilty of double standards
However, Cuba has repeatedly said it is not seeking Posada, but wants him to be tried in Venezuela or before an international tribunal.
Posada, a former CIA collaborator and anti-communist activist who is seeking political asylum, was arrested in Miami just hours after he emerged from hiding to give a series of media interviews.
His public presence enraged Cuban President Fidel Castro, who accused Washington of double standards in its "war on terrorism".
In Havana, about a million Cubans held a protest march on Tuesday demanding that Washington take action against Posada.
One option for Washington would be to turn over Posada to a country other than Venezuela so he would not be sent to Cuba.
Posada, a Venezuelan citizen who lived there at the time of the 1976 plane bombing, was arrested in Venezuela more than 20 years ago, but escaped from prison without being convicted.
State Department counsellor Philip Zelikow told lawmakers last week the plane bombing was an act of terrorism and US authorities were gathering evidence about Posada's suspected role to determine how to treat any asylum request.