Violence flared on two fronts, leaving at least 15 people dead in Croatia and pitting Serbian police against ethnic Albanian protesters in Serbia's Kosovo province. The fresh fighting in Croatia came amid preparations for the first working session of a peace conference organized by the European Community in The Hague. In Kosovo, Yugoslavia's poorest region, baton-wielding police used tear gas to disperse 15,000 to 20,000 ethnic Albanians in Pristina, the southern province's capital. The renewed violence in Croatia came a day after authorities there declared an all-night curfew in 29 municipalities in an apparent effort to exert control over territories held by the Serbs. But the move appeared to have little effect.