Some 800 people were evacuated from the disaster area located on the outskirts of Mantanzas, a town of 140,000 inhabitants 100 kilometers east of Havana, from where the huge plume of black smoke obscuring the sky was visible.
"Cuba has requested assistance and advice from friendly countries with experience in the oil sector," the presidency said in a statement.
Foreign Minister Bruno Rodriguez said that "Cuba's foreign policy is activated to receive help from friendly countries."
The U.S. Embassy in Havana said it was "in touch" with Cuban officials and clarified that "U.S. law allows U.S. entities and organizations to provide disaster relief and response in Cuba." The United States imposes a sanctions regime on the single party in power on the communist island.
On Twitter, Cuban President Miguel Diaz-Canel said that controlling the fire "could take time".
Three injured are in critical condition, three in very serious condition and 12 people are seriously injured, according to the official Granma newspaper. The 17 missing are "firefighters who were in the area closest to the fire" when an explosion took place.
Helicopters were on the job battling the blaze on Saturday, with water hoses brought in using cranes.
- "The sky was yellow" -
The fire broke out late Friday night when lightning struck one of the tanks at the oil depot. In the early morning, the fire then spread to a second tank.
According to Granma, "there was a failure in the lightning rod system which could not withstand the power of the electric discharge".
Ginelva Hernandez, 33, said she, her husband and three children were sleeping when they were awakened by a violent explosion. "We threw ourselves out of bed. When we went out into the street, the sky was yellow," she told AFP. At that time, "people's fear was uncontrollable".
Laura Martinez, a resident near the disaster area, told AFP that she "felt the explosion, like a shock wave".
Hearing a first explosion, Yuney Hernandez, 32, and her children fled their home located two kilometers from the depot. They returned a few hours later and then heard more explosions in the early hours of the morning and sounds "like pieces of the tank falling".
According to Asbel Leal, director of trade and supply at the Cuban Petroleum Union (Cupet), the first tank "contained about 26,000 cubic meters of domestic crude, or about 50% of its maximum capacity" at the time of the disaster. . The second tank contained 52,000 cubic meters of fuel oil.
According to him, Cuba had never been confronted with a fire of "the magnitude of today".
The deposit supplies the Antonio Guiteras power plant, the largest in Cuba, but pumping to the plant has not stopped, Granma said.
This fire comes as the island has been facing supply difficulties since May to meet the increased demand for electricity due to the summer heat.
The authorities must carry out rotating cuts of up to 12 hours a day in certain regions of the country, triggering the anger of exasperated residents who have organized around twenty demonstrations.
The obsolescence of the island's eight thermoelectric power stations, maintenance work and the lack of fuel are hampering electricity production.
Cuba currently has an average electricity distribution capacity of 2,500 megawatts, which is insufficient for peak-hour household demand, which reaches 2,900 megawatts, according to the authorities.
