Venezuela's President Nicolas Maduro gestures as he speaks during a military parade in Caracas, Venezuela, December 12, 2015. [Photo/Agencies]

HAVANA - Retired Cuban President Fidel Castro congratulated Venezuelan President Nicolas Maduro for a "brilliant and brave speech" he gave the night he suffered a severe setback in legislative elections.

"I join the unanimous opinion of those who have congratulated you on your brilliant and courageous speech on the night of Dec 6, barely knowing the verdict of the polls," Castro said in an inspirational note to Cuba's key ally.

Castro, 89, had formed a socialist alliance with Maduro's predecessor, Hugo Chavez. Following Castro's retirement in 2008 and Chavez's death in 2013, that alliance has been continued by Fidel's younger brother and current President Raul Castro, and by Maduro, Chavez's former vice-president who won his own presidential election after Chavez died.

Raul Castro issued a 45-word statement of support beginning "Esteemed Maduro" the morning after the vote. Fidel Castro sent a 537-word "Dear Nicolas," finding glory in Venezuela's history of independence, first from colonial Spain under Simon Bolivar and more recently from the United States under Chavez.

"The millions of children and young people who today attend the best and most modern public schools are those of Venezuela," Castro wrote, praising what he considered the accomplishments of the Socialist Party.

"The same is true of its network of healthcare centers belonging to a people who are brave but impoverished by centuries of looting by Spanish colonialism and later by the big transnationals that extracted from her womb, for over a hundred years, the best of the immense wealth of petroleum with which nature endowed the country."