Dozens of government supporters broke up a silent march by a small group of dissidents marking International Human Rights Day on Sunday, roughing up participants and calling them "mercenaries" and "worms."

It was not immediately known if there were any injuries that required medical attention.

Organized by dissident physician Darcy Ferrer, the demonstration involving less than a dozen government opponents in a public park in Havana's Vedado neighborhood was interrupted as soon as it began by burly men who surrounded and shoved the marchers.

"Long live Fidel and Raul!" the government loyalists chanted, referring to ailing leader Fidel Castro and his brother. "Down with the worms!"

"They are mercenaries!" some of the Castro loyalists shouted of the dissidents.

Another silent opposition protest was scheduled Sunday afternoon by a group of women known as the Ladies in White, who march after Roman Catholic Mass every Sunday to call for the release of their husbands and other Cuban political prisoners.

Although the weekly march has been held regularly for several years, it has only be broken up once, by a group made up mostly of women screaming pro-government slogans.

Many of the husbands and other relatives of the Ladies in White were among 75 dissidents who were arrested during a government crackdown in March 2003 and sentenced to prison terms ranging from six to 28 years.

Cuba accused the activists of working with U.S. officials to undermine Fidel Castro's government — a charge the dissidents and Washington denied.

Those arrested including independent journalists, human rights activists and members of outlawed political parties. Sixteen have since been released on medical parole, leaving 59 still behind bars.