Venezuela's President Nicolas Maduro holds a copy of the country's constitution as he speaks during a news conference at Miraflores Palace in Caracas December 30, 2014. [Photo/Agencies]

CARACAS - Venezuelan President Nicolas Maduro said on Sunday he would only seek the release of jailed opposition leader Leopoldo Lopez if the United States agreed to release a Puerto Rican nationalist currently held in a US prison.

Lopez was arrested in February after he helped launch a three-month wave of opposition demonstrations seeking Maduro's resignation, an effort government critics called free protest but the government said was meant to spark a coup.

Maduro suggested he could send Lopez to the United States if Washington secured the release of Oscar Lopez Rivera, who was convicted in 1981 of seditious conspiracy along with other militants who sought to secure Puerto Rican independence.

"The only way I would use (presidential) powers would be to put (Leopoldo Lopez) on a plane, so he can go to the United States and stay there, and they would give me Oscar Lopez Rivera - man for man," Maduro said during a televised broadcast.

A spokesman for the US Embassy in Caracas said he had no immediate comment on the issue.

US government officials including President Barack Obama have called for the release of Lopez, describing him as a political prisoner, a term Maduro says is more appropriate for Lopez Rivera.

In 1999, Lopez Rivera turned down an offer of conditional clemency by then President Bill Clinton, according to media reports.