Ukrainian special forces exchanged gunfire with a pro-Russia militia in the eastern city of Sloviansk today, with at least one Ukranian officer killed and others wounded on both sides.

Kiev Interior Minister Arsen Avakov said a security service officer had been killed in Sloviansk, where the police station and the security service office had been seized a day earlier by armed men.

He said the fighters who had seized the buildings in Sloviansk had opened fire on Ukrainian special forces sent to the city.

Resistance to the rump Kiev government has spread to several municipalities in eastern Ukraine, including the major industrial city of Donetsk as well as Druzhkovka, Kramatorsk, Sloviansk, Mariupol and Enakiyeve.

Overnight, Mr Avakov also reported an attack on a police station in the city of Kramatorsk.

A video from a local news website showed a group of camouflaged men armed with automatic weapons storming the building.

The website reported that supporters of the “Donetsk People’s Republic” had occupied the administration building, built a barricade around it and put a Russian flag nearby.

It also said three key administrative buildings had been seized in Enakiyeve.

And in Mariupol, south of Donetesk, the city hall was seized by armed masked men.

Around 1,000 protesters built a barricade around the building while armed men raised the Russian flag over the building.

US Secretary of State John Kerry claimed that the attacks “were orchestrated and synchronised, similar to previous attacks in eastern Ukraine and Crimea.”

Mr Kerry threatened that “if Russia didn’t take steps to de-escalate in eastern Ukraine and move its troops back from the border, there would be additional consequences.”

But the Russian Foreign Ministry denied Mr Kerry’s claims and Foreign Minister Sergei Lavrov blamed the crisis on the failure of the Ukrainian government “to take into account the legitimate needs and interests of the Russian and Russian-speaking population,”

Mr Lavrov also warned that Russia may pull out of an upcoming Ukraine summit this week if Kiev used force against “residents of the south-east who have been driven to despair.”