Thousands of Cubans have joined the biggest protests for decades against the island's Communist government.
They marched in cities including the capital Havana, shouting, "Down with the dictatorship!".
Images on social media showed what appear to be security forces detaining and beating some of the protesters.
Cubans have been angered by the collapse of the economy, as well as by restrictions on civil liberties and the authorities' handling of the pandemic.
The protesters were demanding a faster coronavirus vaccination programme after Cuba reported a record of nearly 7,000 daily infections and 47 deaths on Sunday.
Last year, Cuba's largely state-controlled economy shrank by 11%, its worst decline in almost three decades. It was hit hard by the pandemic and US sanctions.
Thousands of pro-government supporters also took to the streets after the president went on television to urge them to defend the revolution - referring to the 1959 uprising which ushered in decades of Communist rule.
President Miguel Díaz-Canel said the protests were a provocation by mercenaries hired by the US to destabilise the country.
"The order to fight has been given - into the street, revolutionaries!" he said in an address on TV.
The top US diplomat for Latin America, Julie Chung, tweeted: "We are deeply concerned by 'calls to combat' in Cuba."
"We stand by the Cuban people's right for peaceful assembly. We call for calm and condemn any violence."