Croatian war veterans on Monday prevented top officials including Prime Minister Zoran Milanovic from joining a march to commemorate the anniversary of the 1991 fall of Vukovar at the start of the Yugoslav wars. The observance was held amid growing tensions between Croatians and minority Serbs in the eastern city sparked by the introduction of bilingual signs on public buildings -- written in the Cyrillic alphabet for Serbs alongside the names in the Latin alphabet for Croats. Veterans opposed to the use of Cyrillic dissuaded the officials, who gathered first at the city's hospital -- a wartime symbol of resistance to Serb aggression -- from joining the traditional march through Vukovar. The officials decided to abandon the observance after some 20 candles had been placed in their way while a few hundred veterans stood nearby, many wearing T-shirts reading, "For a Croatian Vukovar -- No to Cyrillic". Rebel Serbs who opposed Croatia's bid for independence from Yugoslavia captured Vukovar after a bloody three-month siege, marking the start of 1991-95 war, which claimed around 20,000 lives. "Unfortunately, this was more or less expected," Milanovic told state television after the officials decided not to insist on joining the march. Milanovic's center-left government had repeatedly refused to scrap the introduction of Cyrillic on Vukovar's official signs, noting that respect for minority rights was a key condition for Croatia's EU membership. The Balkan state became the European Union's newest member on July 1. War veterans have been smashing the bilingual signs regularly ever since they began appearing in September, clashing with police on several occasions. During Monday's so-called "Memory Column" through Vukovar from the hospital to a memorial cemetery, people from across the country carried candles and waved Croatian flags. The Vukovar hospital, though heavily shelled throughout the siege, stayed open for hundreds of war wounded while coping with inhuman conditions and lacking medicines, electricity, food and water. In late November 1991, Serb soldiers bused some 400 wounded Croats and other non-Serbs from the hospital to nearby Ovcara. Some 260 of them were taken to a secluded pig farm, where they were beaten, killed and buried in mass graves. After the war the city and surrounding region were under U.N. administration; the area was finally reintegrated into Croatia in 1998.