Havana has blamed the US sanctions for perpetuating an economic crisis that has forced people to come out in protest.
One person died and more than 100 others, including independent journalists and dissidents, have been arrested after unprecedented anti-government protests in Cuba, with some remaining in custody, activists said.
A 36-year-old man named by the state news agency as Diubis Laurencio Tejeda died during an anti-government protest on the outskirts of Havana on Monday, the interior ministry said.
READ MORE: Cuba blames US for unprecedented protests
The ministry said it "mourns" his death while the news agency said he had taken part in "disturbances."
Relatives and friends of those detained during and after Sunday's demonstrations engaged in a desperate search on Tuesday for news on their whereabouts.
Cuba's San Isidro free speech protest movement published late on Monday a list on Twitter of 144 people held or reported as disappeared after protestors took to the streets in dozens of cities and towns.
The rallies come as the country endures its worst economic crisis in 30 years, with chronic shortages of electricity, food and medicine - some of the problems perpetuated by US sanctions.
Havana blamed the show of discontent on the United States pursuing a "policy of economic suffocation to provoke social unrest in the country."
Cuba has been under US sanctions since 1962.
Because of the #blocking #Cuba cannot buy the #Temozolamide chemotherapeutic treatment for #tumors #malignant brain that would benefit to patients under 15 years of age with diagnosis Central Nervous System Tumor. pic.twitter.com/YHkURU3zoS— Caricia en el viento☆ (@AvilasFran) July 12, 2021
Meanwhile, demonstrators in Miami expressing solidarity with Cubans shut down a stretch of a major South Florida expressway on Tuesday.
The large group gathered at a busy Miami intersection chanting support for the Cubans, who had taken to the streets in the communist nation Sunday to air grievances about poor economic conditions, among other complaints.
A few miles away, hundreds of supporters gathered for hours Tuesday evening at a park. The peaceful crowd waved flags and cheered on the efforts of island protesters.
Flavia Perez, 16, was brought to the US at age 1. She joined the rally at Tamiami Park, saying, "I'm here to support young Cubans on the island so they have the same opportunities as I have in the US."
In pictures: Protesters shut down part of the Palmetto Expressway in Miami, Florida, as they show their support for the people of Cuba pic.twitter.com/8ShqcfGCY3— TRT World Now (@TRTWorldNow) July 13, 2021