Pro-Russian activists have attacked a police station in the town of Horlivka in east Ukraine, despite warnings form Kiev that they will launch a military operation to secure the region.

The deadline has passed for the ultimatum issued by resident Oleksandr Turchynov for the pro-Russian groups to lay down their arms and vacate officials buildings in the east of Ukraine or face a military crackdown. However, the unidentified militias continue to hold onto key government buildings in Sloviansk and a number of other towns and cities in the region, and have called for a referendum on the future of Ukraine amongst other demands.

Turchynov has signalled support for a national referendum, but has said he is now preparing an “anti-terrorist operation” to regain control of buildings and towns lost to the pro-Russian forces, and blames Moscow for support of the groups.

The country now waits anxiously to see whether Turchynov will follow through with his threat, and whether that action will spark a civil war, which may draw Russia, who has a large array of troops on the Ukrainian border, into the conflict.