On Monday, Condoleezza Rice said a government commission on Cuba had been reconvened and would report by next May on more measures to promote change.

She said the time had come to end 46 years of "cruel dictatorship".

But Mr Castro described the venture as "befuddled" and said the Cuban revolution was stronger than ever.

'Pitiful'

President George W Bush appointed the Commission for Assistance to a Free Cuba in late 2003 under the leadership of Ms Rice's predecessor, Colin Powell.

It received its first recommendations in May 2004.

The proposals are designed to hasten the fall of Mr Castro and prevent his younger brother, Raul, from succeeding him.

Mr Castro asked the National Assembly if there could be "anything more befuddled than having this crazy woman speak of transition [in Cuba]?"

"They are stark raving mad. It's pitiful," he said, quoted by Efe news agency.

Mr Castro also described his revolution as "the sanctuary of universal ethics."

Since the fall of the US-backed dictatorship of Fulgencio Batista in 1959, Cuba has been a one-party state led by 79-year-old Mr Castro.

The US has maintained a strict economic embargo in response to Cuba's communist policies.