Supporters of Cuba's communist government have confronted the opposition Ladies in White group as its members tried to march in Havana.
Around 100 government supporters shouting insults and political slogans surrounded a group of 20 dissidents, who were eventually moved on by police.
The Ladies in White are wives and mothers of political prisoners, some of whom have been recently released.
The government says crowd protests against the dissidents are spontaneous.
The confrontation in Havana came a day after Cuban state television broadcast a documentary alleging the Ladies in White had been seeking funding from the US government.
The programme featured a man thought to be allied with the dissidents, Carlos Serpa, who it said was a Cuban state security agent working under cover to infiltrate the movement.
The Cuban government has long dismissed the Ladies in White as agents of the US working to undermine the communist revolution.
Cuba is in the midst of releasing the last of 52 dissidents it promised to free last July in a deal brokered by the Roman Catholic Church.
But tension has also been high in the past week because 23 February was the anniversary of the death of Orlando Zapata Tamayo, a political prisoner who died after a long hunger strike.
Some Cuban dissidents have been expressing admiration on the internet for the popular uprisings in the Arab world, but there has been no sign of major protests in Cuba.