HAVANA -- An unidentified protester shouting human rights slogans was attacked by Communist Party activists Thursday in a Havana suburb.

The man was set upon by party members who had gathered at Butari Park in Havana's Lawton neighborhood to hail the current meeting of the Congress of the Young Communists Union, eyewitnesses said.

The Communist rally coincided with a ceremony scheduled in the park by dissidents to mark the 50th anniversary of the Universal Declaration of Human Rights.

In the middle of the crowd the man, about 30 years old, shouted ``Long live human rights! Long live democracy! Freedom for political prisoners!'' witnesses said.

The man was said by witnesses to be holding copies of the Universal Declaration of Human rights and the New Testament.

The man was knocked down and dragged to a neighboring street that had been closed to traffic by police. When foreign journalists tried to follow the action, they were roughed up by the pro-government demonstrators. One television cameraman had his camera taken away.

There was no official information about what happened to the man.

At his weekly press conference, Foreign Ministry spokesman Alejandro Gonzalez said he knew nothing of the incident, but added, ``If there is a public disturbance, measures will be taken to resolve that problem.''

Meanwhile, dissidents and government officials disputed the question of political prisoners.

Relatives of four jailed dissidents held a news conference elsewhere in the city to mark the anniversary of the human rights declaration and urged the release of about 300 political prisoners held in Cuba.

Gonzalez denied that the government held any political prisoners.

``Nobody is imprisoned or deprived of his freedom for having a different opinion,'' he said. Those imprisoned ``are counterrevolutionaries who have broken the law,'' the official said.

One of the jailed dissidents' relatives, Magaly de Armas, said that Omar Rodriguez, an independent journalist invited to the press conference, had been arrested.

At the press conference, Armas demanded the immediate release of Vladimiro Roca, her husband, along with Rene Gomez Manzano, Martha Beatriz Roque and Felix Bonne, leaders of the Domestic Dissidence Working Group.

The four were jailed in July 1997 and accused of sedition for the publication of a manifesto titled The Homeland Belongs to All, heavily critical of Cuba's Communist Party and President Fidel Castro's government.

They have yet to stand trial, although prosecutors have asked for six years imprisonment for Roca and five years for each of the other defendants.

In Washington on Thursday, President Clinton mentioned the imprisoned members of the Domestic Dissidents Working Group in his speech marking the rights declaration's anniversary and stated that ``we make common cause with them all.''

The president was critical of the situation ``in Cuba, where persons who strive for peaceful democratic change still are repressed and imprisoned.''

Also on Thursday, the Archdiocese of Havana released a bulletin marking the anniversary of the human rights declaration. In it, Cardinal Jaime Ortega, archbishop of Havana, wrote that ``a man whose social rights are not assured is not treated with dignity as a person. Neither is a man whose personal rights to physical and moral integrity, to personal, civil and political freedom are not guaranteed.''