Celebrations were held in Santiago to commemorate the 55th anniversary of the revolution in Cuba.
The city has been the scene of the island's most important historic events and was the birthplace of the revolution.
President Raul Castro on Wednesday gave a speech in the same place where his brother Fidel announced to the world on 1 January 1959 the victory of the armed uprising against the rule of Fulgencio Batista
"It's been 55 years of constant struggle against the plans of 11 US administrations, that with varying hostility, have not stopped in their goal to change the economic and social regime brought about by the revolution," Castro told a crowd of about 3000 people, including revolution veterans.
Cuba blames a long-standing US embargo for strangling its economy but Raul's government has also acknowledged that it must reform the state-run economy with a gradual opening to private enterprise.
This year the administration pushed economic reforms to "modernise" the Cuban socialist model.
"The revolution's programme will be updated every five years so that it can always answer to the true interests of the people and promptly correct any errors," said Castro in the televised speech.
"This will also ensure the continued development and deepening of our social democracy."
After taking power, Raul quickly legalised computers and cell phones and removed restrictions on Cubans entering tourist hotels.
In 2013, he approved a measure to allow Cubans to travel abroad without special permits, and recently eliminated a dual currency system.
For 48 years, Cuba was governed by Fidel, who became seriously ill in July 2006 and was replaced by Raul, first on an interim basis.
Raul was then elected president in 2008, and re-elected in 2013 for another five year term.