Cuban authorities were still battling Tuesday to restore power and water supplies, days after Hurricane Irma seriously damaged its generating stations.

"Due to severe damage Hurricane Irma caused in all thermoelectric power plants, we cannot estimate how long it will take to recover and fully enable electric power," said Yuri Villamonte, deputy minister for energy and mines.

Damage to the Matanzas thermoelectric station remains a key concern because it serves the capital Havana's population of two million, which largely remained without power or water.

"We are working to normalize the situation," said Ines Maria Chapman, head of Cuba's national institute of hydraulic resources, without giving details.

Villamonte said he remained hopeful that power would be restored "sooner rather than later" because electricity supply was already back up in most of the eastern provinces.

The international airports in Havana and the resort city of Varadero, which had closed for three days, reopened.

Bus services resumed around the country, while schools and universities not directly affected by the hurricane reopened.

In Havana, brigades of volunteers joined municipal workers to help clear the streets of trees, rubble and other debris.

Police directed traffic at intersections to fill in for traffic lights that had been swept away in the maximum-strength Category Five hurricane.

However, Havana's sprawling Malecon esplanade, which was submerged by seawater during the hurricane, was still closed to traffic.