Supporters of the ruling Sandinista party used force on Wednesday to break up a group of activists gathered in the Nicaraguan capital to mark the 60th anniversary of the Universal Declaration of Human Rights.

Followers of President Daniel Ortega fired homemade mortars, hurled stones, and beat and pushed a crowd made up mainly of government opponents.

The Sandinistas, who were holding their own march for International Human Rights Day, snatched signs from the rival protesters and took control of the El Güegüense rotunda in southwest Managua.

On the placards and signs carried by the activists were phrases like "No to election fraud" and "Where's my vote?" - an allusion to the disputed Nov. 9 nationwide municipal elections.

After surrendering the rotunda, the opposition marchers continued their trek within a police cordon to avoid further violent incidents.

"What occurred today is regrettable," one of the organizers of the opposition event, Bayardo Izaba, told Efe, going on to announce that his group would file a complaint about the incident with the United Nations and the Organization of American States.

"We're going to report the violation of our human rights, of the freedom of expression, demonstration and association which we were subjected to so that this (Ortega) government is embarrassed and learns to respect us," he said.

Managua municipal official Sixto Ulloa, meanwhile, said that the incident was provoked by "two ladies who were on the other side of the police (cordon, who) started shouting and provoking."

He said that the Sandinistas did not beat or attack anyone and that although there were arguments, he called that "part of (Nicaraguan) folklore."

The already tense relations between the Ortega government and its opponents have grown worse since last month's municipal balloting, which, according to the official results, left the Sandinistas in control of a majority of Nicaragua's cities, including Managua.

But the opposition rejects the official tallies as fraudulent and is demanding that the elections be repeated.