"I call on all Vukovar citizens to behave in a dignified way so that yesterday's rioting does not happen again," Sabo said, recalling that dual-alphabet signs had been put up on a kindergarten and a secondary school in the town in 1998 and no one had tried to remove them then.

"If those signs don't bother anyone, I don't know why yesterday's ones do, unless someone deliberately wanted to cause chaos in Vukovar," the mayor said. He wondered how it was possible that the protesters had not been irritated by the Town Council's decision in 2009 by which the HDZ, the Croatian Party of Rights (HSP) and the Independent Democratic Serb Party (SDSS) introduced bilingualism in the town.

Sabo called for peace and tolerance so that "we don't destroy in one day all that we have been building in the last 15 years since the peaceful reintegration of the Croatian Danube region."

The Vukovar-Srijem County Police Department said that three of the six protesters detained had been released after questioning, while the remaining three would be detained until further notice. Their identities were not revealed.

One of the persons released was Stevan Culej, a retired special police officer, who told the press  that the police had treated him well during the questioning. He said that although he knew he would be charged with incitement to rioting he would continue to support the protests because he wanted Vukovar to be declared a special site of reverence for all Homeland War victims so that "the blood that was spilt in this town" would never be forgotten.

Over 500 protesters rallied in the town's centre on Tuesday morning and headed for the Social Welfare Centre on which dual-alphabet signs had been put up. The entry to the building was surrounded by a protective fence with a large number of riot police inside and outside the fence so that demonstrators did not even attempt to push their way to the signs.