ZAGREB, Croatia (AP) _ At least seven ultra-nationalists were arrested Tuesday for harassing anti-fascist demonstrators at an annual celebration of the victory over the Nazis in World War II, police said.

Police said seven people had been arrested for trying to provoke a clash between the two rival groups, who numbered about 2,000 people in all. State-run television later reported 22 people had been arrested. At least one anti-fascist demonstrator was also believed to have been arrested.

For the last decade, anti-fascist groups have been holding rallies at a popular downtown square on May 9, known as V-Day, demanding that the government restore the old name of the square, which honored antifascism.

But they have regularly met resistance from supporters of late authoritarian President Franjo Tudjman's nationalist party, which changed the name of the square in 1991 to commemorate Croatia's historical heroes.

The nationalists shouted insults and threw fruit, eggs and flares at those who joined the rally, but police intervened quickly, detaining the worst troublemakers. About 500 police had been stationed in the square to keep order.

Last year, Zoran Pusic, the leader of the civil rights group Council for Civil and Human Rights, lost a tooth in the melee and the current President Stipe Mesic, was also attacked. Thirteen offenders were arrested.

On Monday, Mesic delivered a speech expressing support for the restoration of the old name.

Right-wing sentiments have flared in Croatia since Tudjman's nationalists lost power in elections early this year and in response to the new pro-democratic government's policies to comply with an international war crimes tribunal and return rebel Serb refugees.