Ukraine has dispatched special forces in response to the seizure of a police station in a small eastern town, while tensions in the country's Russian-speaking regions intensify.
The Ukrainian Interior Ministry said about 15 unidentified armed men, who were wearing camouflage clothing and balaclavas, stormed the building in Slovyansk on Saturday. The town is about 90km south of Donetsk, where pro-Russian protesters briefly took over the prosecutor's office, before riot police arrived.
Interior Minister Arsen Avakov had pledged a "very tough response" to the seizure. In a post on Facebook, he said: "The response will be very tough, because there is a difference between protesters and terrorists."
Another government building in Donetsk has for nearly a week been occupied by protesters demanding greater autonomy in the region.
Ukraine's eastern industrial heartland was the support base for Kremlin-friendly President Viktor Yanukovich, who was ousted in February after months of protests over his decision to ditch an EU trade pact in favour of closer ties with Moscow. Last month, the Crimea region voted to secede and was annexed by Russia.
Lack of trust
Meanwhile in the eastern city of Luhansk, negotiations between protest leaders and a delegation from Kiev were taking place inside an occupied police building, Al Jazeera's Hoda Abdel-Hamid reported, adding that the protesters wanted guarantees due to lack of trust in Ukraine's new government.
They also demanded the guarantee for amnesty and a southeastern army "that would be within the framework of the national army, but led by local command".
In a video posted online from Slovyansk, protesters hoisted the Russian flag above the captured building. Videos also showed several men with machine guns guarding the entrance to the police station.
The AFP news agency reported that they were all wearing St George's ribbons, a symbol of the Soviet Union's victory in the Second World War that has become a symbol of pro-Russian protesters in eastern Ukraine.
The town's mayor, Nelya Shtepa, said on local television that she was holding talks with the occupiers who she insisted were from the area.
The protesters in Donetsk, who have held the regional administration building since Sunday, initially called for a referendum on secession but later reduced the demand to one on autonomy, with the possibility of holding another later on whether the region would remain part of Ukraine or seek to become an autonomous region within Russia.
On Friday, Prime Minister Arseniy Yatsenyuk told leaders in Donetsk that he was willing to cede more power to eastern regions.
Eastern Ukraine has a high proportion of Russian-speakers and many of them fear that the acting government, which took over when Yanukovich fled to Russia in February, will repress them.
The Ukrainian government has accused Russia of fomenting unrest in eastern Ukraine in a bid to derail next months' presidential election in the country.