The explosion ripped through the legendary Hotel Saratoga in the centre of Havana. The cause of the explosion is unknown.
Rescuers are working on the scene. People may have been buried under the rubble of the hotel.
The Cuban authorities have announced that the explosion killed at least four people. The authorities have excluded the version of a terrorist attack.
Hotel Saratoga is located in Old Havana, across the street from the Capitol. It was built in 1880 and renovated in 2005.
The British press has recently reported that Russia was going to conduct a nuclear test either on the borders with Ukraine or in the Black Sea.