Havana,  Cuban authorities have said that the US embargo on the island nation has prevented a shipment by Chinese electronics giant Alibaba which includes of masks, ventilators and testing kits to detect the novel coronavirus.

"Things are getting ever more difficult for Cuba. Not even in times of a pandemic are Cubans allowed to breath easily," Efe news quoted Cuba's ambassador to Beijing, Carlos Miguel Pereira, as saying to the local media, telling how the US shipping company hired by Alibaba refused to send supplies to Cuban ports.

The US company "refused at the last minute" to send the supplies to the Caribbean nation, hindered by the rules of the "blockade", as Cuba calls the economic, financial and trade embargo Washington has maintained against the island since 1962 and which has been strengthened under the Donald Trump administration.

The embargo prevents, among other things, the island from using the US dollar in international transactions, prohibits Cubans from buying a product with more than 10 per cent US components and establishes that vessels that dock in Cuban ports must then wait 180 days to enter US waters or ports.

The Trump administration has tightened the restrictive measures against Cuba to try and suffocate its already fragile economy in reprisal for Havana's aid to the Venezuelan regime of Nicolas Maduro.

The aid announced by Alibaba founder Jack Ma includes two million medical masks, 400,000 rapid testing kits and 104 ventilators to be sent to 24 countries in Latin America and the Caribbean, including Cuba, Argentina, Brazil, Chile, Ecuador, the Dominican Republic and Peru.

However, "one of those shipments could not get to its final destination", the Cuban envoy to China confirmed, thanking the Alibaba founder "for having thought" about the Cuban people and "for the efforts he is still making for his foundation's contribution to finally arrive at its destination".

There are many voices being raised calling for Washington to lift its restrictions on countries like Iran, Venezuela and Cuba, at a time when the coronavirus pandemic is hitting the healthcare systems and economies of the world quite hard.

An online campaign on the citizens activism Web site Change.org launched by Cubans living in the US has already collected more than 15,800 signaures calling on the Trump administration to lift the embargo.

Cuba has reported 212 confirmed coronavirus cases with seven deaths.

The Cuban government on Tuesday announced the complete closure of its borders and strengthened its measures to combat the epidemic, including suspending the huge International Workers' Day parade scheduled for May 1.