DONETSK, Ukraine — Pro-Russian separatists on Monday seized a police building in yet another city in Russian-leaning eastern Ukraine, defying government warnings that it was preparing to act against the insurgents. Dozens of angry men hurled rocks, smashed the windows and broke into a police station in the city of Horlivka not far from the border with Russia, while hundreds of onlookers cheered them on. Thick white smoke rose from the entrance to the building, from which the insurgents hoisted the Russian flag. The events in Horlivka were the latest sign of trouble in Russian-speaking eastern and southern regions, in which pro-Russian gunmen have seized or blocked government buildings in at least nine cities demanding more autonomy from the central government and closer ties with Russia. Oleksandr Sapunov, one of the men who took part in storming the police building in Horlivka, said the insurgents were fighting against appointees of the Kiev government, including the local police chief, and wanted to appoint a leadership of their own. “The people came to tell him that he is a puppet of the Kiev junta and they won't accept him,” Sapunov said. Kiev authorities and Western officials have accused Moscow of instigating the protests, saying the events echoed those in Crimea, which was annexed by Russia last month. Ever since pro-Russian President Viktor Yanukovych fled to Russia in late February, Russia has demanded constitutional reforms that would turn Ukraine into a loose federal state. After refusing demands for a referendum by separatists in the east, acting President Oleksandr Turchynov indicated Monday that holding a nation-wide referendum on the nation's status was a possibility and that such a vote could be conducted on May 25, along with presidential elections. Turchynov expressed confidence that Ukrainians would vote against turning the country into a federation and against its break-up. Meanwhile, a deadline set by the Ukrainian government for pro-Russian gunmen to leave government buildings in eastern Ukraine and surrender weapons passed early Monday, with no immediate sign of any action to force the insurgents out. Turchynov had issued a decree Sunday that those protesters who disarm and vacate government offices in several cities in the Russian-leaning east of the country by 0600 GMT Monday will not be prosecuted. — AP