Director of National Intelligence John Negroponte, AFP PHOTO

"Everything we see indicates it will not be much longer... months, not years," Negroponte told the Post.

However Negroponte, the top US intelligence official, gave no details in the interview to back up his statement.

Castro, 80, handed over the reins of power on July 31 to his brother Raul Castro, the army chief, after undergoing intestinal surgery. He has not been seen in public since July 26.

Raul Castro has reached out to the United States in the past four months, calling for negotiations.

The United States and Cuba do not have full diplomatic relations, and Washington has an economic embargo on the only one-party communist state in the Americas.

On Wednesday the top US diplomat for Latin America indicated that the United States had yet to find a reformer in the communist Cuban government, but did not flatly rule out dialogue with Havana in the context of a political opening.

On Friday a bipartisan group of 10 US lawmakers, all supporters of easing US sanctions on Cuba, were to depart for Havana to meet with top Cuban officials.