Hundreds of thousands of Cubans have joined a May Day rally in Havana to protest a more-than-six-decade US trade embargo of the island and Washington's restrictions on its international medical missions.

Thursday's rally was the first major demonstration since 2022, although the communist-ruled nation, which is mired in a deep economic crisis, has seen several smaller protests over a crippling shortage of fuel.

The demonstrators filled a large avenue stretching from the famous seafront Malecon esplanade to the seat of government in Revolution Square.

A group of doctors and nurses marched past a memorial to nationalist hero Jose Marti chanting "Down with the blockade" and "Long live free Cuba."

They were watched by former president Raul Castro, brother of the late Fidel, and current president Miguel Diaz-Canel.

Trump's sanctions on the island

On his first day back in office, US President Donald Trump reversed his predecessor Joe Biden's decision to remove Cuba from a list of state sponsors of terrorism, paving the way for tighter sanctions on the island.

A month later, the United States expanded visa restrictions over Cuba's dispatch of doctors overseas, a decades-old program that provides Cuba with critical hard currency and influence but which Washington called "forced labour."

"It's important to come today to defend the revolution," Alexander Garcia, a 50-year-old laboratory technician, who arrived at the rally on crutches, told the AFP news agency.

The leader of the Workers' Central Union of Cuba, Ulises Guilarte, accused the Trump administration of trying to "cause shortages and destabilise the country."

He termed Washington's campaign against Cuba's medical brigades programme "perverse."