Gunmen have seized a police station and other government buildings in Ukraine's eastern industrial heartland amid a tense deadlock in the country's east, where armed pro-Russian protesters have barricaded themselves inside government buildings and demanded independence from Kiev.

Ukraine's interior minister, Arsen Avakov, said another group of gunmen tried to storm the Donetsk regional prosecutor's office but was repelled.

The early morning raid on the police station happened in Slavyansk, a town about 35 miles north of the regional capital, Donetsk. The men collected weapons and distributed them to their supporters. A second group later took the headquarters of the state security service.

"Armed men in camouflage fatigues have taken the police station in Slavyansk," Avakov wrote on his Facebook page. "Here, our response will be very severe."

A local police official told Kiev's private Channel 5 television that the raid was staged by six men who had fired several shots into the air before storming the station. It was not immediately clear how the local police responded or whether the gunmen had taken any hostages.

Avakov said that Ukrainian special forces had been dispatched to the scene.

"There is zero tolerance for armed terrorists," he said.

The interior minister added that a separate group of assailants had tried to take control of the prosecutor's office in Donetsk.

"They have all been expelled. The building has been clear of unauthorised personnel," he wrote.

"Another self-declared defence minister has been arrested."

Protesters in the eastern Ukrainian cities of Donetsk, Kharkiv and Luhansk seized government buildings on Sunday. While police managed to clear the Luhansk office swiftly, protesters in Donetsk and Kharkiv remain entrenched.

The Donetsk adminstration centre remains under the control of several hundred gunmen who have proclaimed the creation of their own "people's republic" and called on the Russin president, Vladimir Putin, to send in troops.

In a further sign of growing tensions between the two countries, Ukraine's state-run energy company Naftogaz on Saturday suspended gas payments to Russia.

Russian gas giant Gazprom earlier this month increased gas price for Ukrainian consumers to $485 per 1,000 cubic meters (tcm) from $268 for the first quarter, saying Kiev was no longer eligible for previous discounts.

Naftogaz chief executive Andriy Kobolev told the Zerkalo Nedely weekly that payments would be suspended until the conclusion of price negotiations.