Tomislav Josic told a news conference in Vukovar today that the rally would start at 1205 hrs on Sunday in Zagreb's main square.

"We will be more vocal and clearer in our opposition in Zagreb than we were in Vukovar," Josic said.

The rally in that eastern Croatian town was organised on 2 February by the Committee for Defence of Croatian Vukovar, comprising people who defended the town against Serb paramilitaries backed by the Yugoslav army during the war in the early 1990s, disabled war veterans, former inmates of Serb-run detention centres, children of defenders who were killed or went missing during the war, and officers of the Croatian armed forces and the police. They were joined by residents of Vukovar and people who came from throughout the country.

The committee believes that the time has not come yet for giving Cyrillic script the same status as Latin script, stressing that it would lead to ethnic intolerance and jeopardise the peace in the town. It wants Vukovar to be exempt from the Constitutional Law on the Rights of National Minorities or that the introduction of bilingualism in the town be placed under a moratorium of at least 50 years.

According to the 2011 census, local Serbs account for just over one third of the population in Vukovar, which enables them to exercise certain rights such as signs written in the alphabet this minority uses.

On 5 February, the European Commission declined to comment on the latest developments regarding plans to introduce dual-alphabet signs in Vukovar and the opposition to possible Cyrillic signs in the eastern Croatian town.

We do not comment on details in relation to the events in Vukovar. We only want to remind about two European Union principles: the rule of law which means that the laws should be respected and the government should ensure the enforcement of laws. The other principle is reconciliation and protection of minorities. These principles are an integral part of the values embraced by the EU, said European Enlargement Commissioner spokesman Peter Stano then when asked to comment on rising opposition to the possibility of installing Cyrillic signs in Vukovar.

However, the last monitoring report regarding Croatia released by the EC on 26 March reads that "it is welcome that the government continues to ensure the implementation of the constitutional provisions on the use of the Cyrillic script in the city of Vukovar, where Croatians of Serb ethnicity account for 38.5% of the population."

Opponents of bilingualism say that despite the constitutional provision on bilingualism, the Croatian executive authorities should also take into consideration that there is another constitutional provision envisaging that certain rights may be restricted if they are considered harmful in a given period.

These most vociferous opponents also warn that local Serbs, even those who participated in the military aggression against and occupation of eastern Croatia in 1991, have in the meantime been amnestied and allowed to exercise many minority rights, which also enables that some of them may only formally be registered in Vukovar but their actual place of residence is in Serbia or Serb-populated areas in Bosnia and Herzegovina, all of which has led to "a contrived image of the ethnic structure in Vukovar" and to the "current absurd situation" in the city.