Cuba has completely run out of diesel and fuel oil, the country's energy minister Vicente de la O Levy has said.

In an interview with state-run media, de la O Levy said there were limited amounts of gas available, but that Cuba's energy system was in a "critical" state as a US-led blockade of oil to the country squeezes supply.

Scattered protests against power cuts broke out in the Cuban capital, Havana, on Wednesday, according to the Reuters news agency.

The US this week reiterated its offer of sending $100m (£74m) in aid to the country in exchange for "meaningful reforms to Cuba's communist system".

"The sum of the different types of fuel: crude oil, fuel oil, of which we have absolutely none; diesel, of which we have absolutely none - I am being repetitive - the only thing we have is gas from our wells, where production has grown," de la O Levy said.

Under the US blockade, parts of the capital Havana have been plunged into 20 to 22-hour blackout periods, he continued.

He also acknowledged that the situation in the country has been "extremely tense".

Hospitals in the country have been unable to function normally, while schools and government offices have been forced to close. Tourism, an economic engine for Cuba, has also been impacted.

Cuba normally relies on Venezuela and Mexico to supply oil to its refinery system. However, the two countries have largely cut off supplies since US President Donald Trump threatened tariffs on countries that send fuel to Cuba.

Last week, US Secretary of State Marco Rubio said Havana had rejected a US offer of $100m (£74m) worth of humanitarian aid, a claim that Cuba has denied.

The US State Department repeated its offer on Wednesday, saying the humanitarian assistance would be distributed in coordination with the Catholic Church and "reliable" humanitarian organisations.

It continued: "The decision rests with the Cuban regime to accept our offer of assistance or deny critical living-saving aid and ultimately be accountable to the Cuban people for standing in the way of critical assistance."

Washington's blockade on the country ramped up in early May when the US targeted senior Cuban officials in a wave of sanctions accusing them of committing "human rights abuses".

Cuban Foreign Minister Bruno Rodriguez called the sanctions "illegal and abusive".