ZAGREB, Croatia (AP) — Wielding hammers, Croatian war veterans on Monday tore down signs written in the Serbian Cyrillic alphabet that were put up on official buildings to boost minority rights in the new EU nation.

Dozens of angry veterans pushed away police guarding the state buildings in Vukovar, an eastern town on the Danube that was heavily damaged by the Serb-led Yugoslav army during Croatia's 1991 war for independence. Thousands were killed in the conflict.

Vukovar has a sizable Serb minority and having official signs in both the Croatian Latin alphabet and Serbian Cyrillic are in line with the country's law on minority rights. Vukovar war veterans, however, say the Cyrillic signs insult Croatian war victims.

Police said that several people were detained and four policemen were slightly injured during the skirmishes with the demonstrators.

Croatian state TV reported that about 300 people gathered later on Monday demanding the release of the detained protesters.

Croatia's president and the government condemned the sign destruction as "chauvinist violence."

Croatia became the European Union's 28th member in July. But about two decades after the war, ethnic tensions between Croats and Serbs are still simmering, particularly in Vukovar.