Cuba's former President Fidel Castro (R), Bolivia's President Evo Morales and Venezuela's President Nicolas Maduro sit together in a van in Havana, Cuba, August 13, 2015. [Photo/Agencies]

HAVANA - Cuban revolutionary leader Fidel Castro celebrated his 89th birthday Thursday with a surprise visit to Bolivian President Evo Morales, who was in Havana for the occasion.

Fidel, accompanied by Venezuelan President Nicolas Maduro, who was also in Havana, "surprised" Morales "at the hotel where he is staying," the Bolivian News Agency (ABI) reported.

Morales was expecting to visit Fidel at his home, so "the indigenous head of state was greatly surprised to see his revolutionary mentor, who is in good health despite his advanced years, arrive in a van," ABI said.

A photo accompanying the story showed Fidel, wearing a navy blue baseball cap and checkered shirt under a white-striped windbreaker, sitting in a van, with Morales and Maduro seated to his right.

A delegation from the 11 member countries of the Bolivarian Alliance for the Peoples of Our America (ALBA), a regional integration bloc spearheaded by Venezuela's socialist government, was to travel to Havana to take part in a series of commemorative events, including concerts and tributes, ABI said.

The celebrations come a day before US Secretary of State John Kerry officially inaugurates his country's embassy in Havana, cementing the restoration of Cuba-US ties after half a century.

The ever outspoken Fidel, who retired from power in 2006, published an editorial in state daily Granma Thursday, in which he calls on the United States to compensate Cuba for the hundreds of millions of dollars in potential revenue lost over the decades due to the US-led trade embargo.

"Cuba is owed compensation equivalent to damages, which have reached many millions of dollars," wrote Fidel, who led the 1959 Cuban Revolution that overthrew US-backed dictator Fulgencio Batista.