The aircraft, a twin-engined turboprop Antonov AN-26, had taken off at 6:38 a.m. (0638 ET) from Playa Baracoa, just outside Havana, and crashed into the Loma de la Pimienta mountain some 80 km (50 miles) westwards.
“The eight military personnel on board, including the crew, died,” the ministry said in a statement published by state-run media.
“A commission of the Ministry of the Revolutionary Armed Forces is investigating the causes of the accident.”
The majority of planes flown in Cuba were produced in the Soviet Union. Antonov produced the AN-26 planes in Kiev between 1969 and 1986.
The last major plane crash in Cuba was an Aero Caribbean flight that went down in flames in central Cuba in 2010, killing all 68 people aboard. That plane was a European-manufactured ATR-72-212.