Some 50 boats took part in a protest regatta in Cuba's Cienfuegos Bay Sunday, accompanied by bikers and people waving flags on the shore, to demand an end to US sanctions amid the coronavirus pandemic.
The communist island claims the sanctions, tightened under ex-president Donald Trump, have prevented it from producing the vaccines it needs for its population.
Under President Joe Biden, "the United States government has kept intact Trump's measures that harm the Cuban people," Foreign Minister Bruno Rodriguez said on Twitter.
The country of 11.2 million people has reported more than 141,000 cases of Covid-19 and 950 deaths.
It started immunizing members of the public this month with two locally-produced vaccines that have yet to complete clinical trials.
Under American sanctions since 1962, Cuba has a long tradition of making its own vaccines, dating back to the 1980s, and is working on five coronavirus candidate shots. It has not bought or sought coronavirus vaccines from elsewhere.
From the coast of Cienfuegos Bay, 245 kilometers (152 miles) southeast of Havana, a group of young Communist Party supporters encouraged the non-competitive regatta participants with messages including: "No to the genocidal and inhumane blockade."
"This regatta is a condemnation and denunciation... of the criminal blockade," charged Maylin Leon, 28, an organizer of the event and head of the ideology department of the Communist Party of Cuba's youth branch.
Fishing boats and kayaks also participated in the event, as did bikers on the shore waving Cuban flags and shouting the revolutionary slogan "Fatherland or Death."
Cuba's relations with the United States have been at a low since then-president Trump reinforced sanctions following an historic but temporary easing of tensions under Barack Obama between 2014 and 2016.
Washington accuses Cuba of human rights violations and is angered by its support for leftist Venezuela.
On the campaign trail, Biden had promised to bring back some of Obama's policies to seek a normalization of ties, but as president, he has yet to make an announcement.