HAVANA, Cuba (CNN) -- Havana is ready and willing to start a dialogue with Washington, Cuban President Raul Castro said in a speech to parliament Saturday, but warned that political and regime change are not up for negotiation.

Raul Castro warns his critics there will not be any upcoming change in Cuba's political philosophy.

"They didn't elect me president to restore capitalism in Cuba, nor to surrender the revolution," Castro said to loud applause. "I was elected to defend, maintain and continue perfecting socialism, not to destroy it."

He added that those expecting political change after the death of former President Fidel Castro and his generation were "condemned to fail."

Castro ceded the presidency to his younger brother, Raul, last year but has retained leadership of the Communist Party, the only legal political party in Cuba.

There has been speculation that the elder Castro will step down from that post as well at the next Communist Party Congress.

Fidel Castro, who had run Cuba since 1959, has not appeared in public since abdominal surgery in 2006.

Raul Castro's speech was given to a biannual session of the National Assembly and largely focused on Cuba's economy. Watch a report on the state of the Communist Party »

Castro called some of the measures taken by the Obama administration "positive," but said, for Cuba, the main stumbling block remains the U.S. trade embargo, which has been in place in one form or another since 1960.

Castro also repeated Cuba's offer to "sustain a respectful dialogue between equals" with the United States.

The Obama administration, on the other hand, has insisted on signs of change from Cuba before he makes any more overtures.

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