Ukraine's Interior Minister Arsen Avakov said that fighting between separatist militiamen and government forces in the Donetsk region's Mariupol on Friday had resulted in the deaths of 21 people.
Avakov posted on his Facebook page that 20 "terrorists" had been killed and four were captured during Ukrainian government forces attempted to take back the city's police headquarters from 60 separatists, an operation that according to the minister resulted in the death of one Ukrainian soldier and injures to five others.
Avakov and other media reports said that the building had caught fire during the skirmish in the city, part of the self-proclaimed "People's Republic of Donetsk" that has called for independence from Ukrainian authorities in Kiev.
Reuters reported late Friday afternoon that 3 had been killed and 25 injured as a result of the violence, citing medical workers in the city. A separatist militia representative earlier told Interfax that from preliminary data the death toll could be anywhere from one to eight people
Mariupol's police headquarters was retaken by separatists on Thursday after having been under government troops' control for mere hours.
Key buildings in Mariupol, a city of less than half a million people on Ukraine's southern coast, were taken over by separatists in mid-April and have traded hands between Ukrainian government forces and separatists multiple times in the last two days.
A video on YouTube supposedly showing Mariupol captured images of with Ukrainian flags rolling through the streets of the city on Friday morning.