Cuba has been suffering from an energy crisis since January, when US forces captured then-Venezuelan president Nicolas Maduro and deprived Havana of its main source of oil.

Diaz-Canel insisted last week that he would not resign under pressure from the United States and called for dialogue.

China's foreign ministry reiterated Beijing's support for the island when asked about the comments on Wednesday.

"China firmly opposes coercive diplomacy and will resolutely support Cuba in safeguarding its national sovereignty and opposing foreign interference," spokesman Guo Jiakun told a regular news conference.

Beijing and Havana are longtime socialist allies, and Chinese authorities have consistently opposed a decades-long US trade embargo on the island.

Tensions intensified in January as US President Donald Trump warned that Cuba "is ready to fall".

The US president also said Cuba should make a deal or face consequences.

However, the United States allowed a shipment of crude oil from a Russian tanker to be unloaded in Cuba in late March.

Russia said this month it would send a second ship carrying oil to Cuba.