Anti-government protesters on Saturday seized a regional administration building, news reports said, and officials warned that police could storm the Kiev city hall to free two policemen allegedly captured by demonstrators.

Protesters have occupied the city hall for nearly two months and turned into a makeshift dormitory and headquarters. Protesters deny they are holding the officers.

A ministry statement warned that police would storm the building if the two officers were not released. It said another officer who had been injured while being seized had been released and was hospitalized in serious condition.

An attempt by police to storm the building would likely set off new clashes.