Pyongyang's state-controlled KCNA reported Monday that Choe Ryong Hae, vice chairman of North Korea's Workers' Party, had departed for Havana to attend the ceremonies for Castro, who died Friday at age 90.
"Comrade Choe Ryong Hae left Pyongyang on Monday as the head of a delegation representing the party and the state in order to express condolences for the death of Fidel Castro, supreme leader of the Cuban revolution," KCNA stated.
North Korea and Cuba first established diplomatic ties in 1960 and have maintained a friendship that has survived beyond the Cold War.
As recently as June, Cuban Vice President Salvador Valdes Mesa traveled to North Korea as a special envoy and met with Choe in Pyongyang.
North Korea has ordered a three-day mourning period for Castro, according to Workers' Party newspaper Rodong Sinmun. Kim described Castro as a "close friend and comrade of the Korean people," RT reported.
Castro's death has also elicited a response from Tokyo.
Japan's Shinzo Abe, who met with Castro in September in Cuba, will not be attending the memorial services, but the government has decided to send Keiji Furuya, election strategy chief of the ruling Liberal Democratic Party and head of an association of lawmakers promoting Japan-Cuba friendship, according to Kyodo News.
Furuya left Japan on Monday to attend the Cuban memorial service on Tuesday.
In Havana, Furuya is expected to meet with key Cuban officials, according to Japanese press reports.
Abe has already expressed his condolences for Castro's death.
South Korea has no diplomatic relations with Cuba, but on Tuesday Seoul's foreign ministry expressed condolences to the Cuban people and used a respectful term for "death" in its message, signaling a positive approach to mark the occasion, according to local newspaper Maeil Business.
Seoul also said it intends to strengthen cooperation and exchange with Cuba.