An Orthodox priest and pro-Russian protesters attend a rally in front of an occupied police station in Slaviansk, Ukraine, 13 April. after armed pro-Russian activists seized police buildings in the city on 12 April. At least one Ukrainian special forces officer was killed and five wounded in the eastern city of Slaviansk, acting interior minister Arsen Avakov said, as they tried to dislodge armed pro-Russian activists from police buildings. Any casualties among the pro-Russian resisters was not known. EPA/ANASTASIA
Ukraine's interior ministry says one Ukrainian officer was killed and five wounded on Sunday during an "anti-terrorist" operation by Ukraine after pro-Russian forces took control of the police HQ in the eastern city of Slaviansk, alongside similar raids by camouflaged men on police stations in Kramatorsk, Druzhkovka, Mariupol and Yenakievo on Saturday.
The Russian RIA news agency reports one pro-Moscow fighter was killed and two wounded in the exchange of fire, as tension increased in eastern Ukraine.
As reports of the number dead and wounded varied, Ukrainian interior minister Arsen Avakov said that there were "wounded on both sides" in the gun battle as Ukrainian state forces tried to retake the police HQ in Slaviansk.
Avakow claimed the pro-Russian forces had "around 1,000 supporters" there.
Armed men have also set up road blocks around the city, which lies about 150 km from the Russian border.
The main local government building in Donetsk has also been occupied for the last week by pro-Russian groups.
Ukraine "is justified in treating the separatists as terrorists," Poland's prime minister Donald Tusk said on Sunday as the interim Ukrainian government stepped up efforts to contain the situation.
"Nobody would, or should, encourage Ukraine authorities into a radical act but there comes a time when the Ukraine state must act, in order to show it does not accept these actions," Donald Tusk added and blamed Russia for inflaming the situation in Ukraine.
"We all know who is causing the tension there," he said.
"t's time to consider the next stage of sanctions by the EU against Russia," Polish Radio's IAR news agency reports Donald Tusk as saying.
“The manner in which we react now shall determine what stand the Union will take in times of a future crisis,” Tusk concluded.
US Ambassador to the UN Samantha Power told the ABC broadcaster that there were "telltale signs of Moscow's involvement" and added that sanctions already imposed on Moscow were having an effect.
"I think we've seen that the sanctions can bite and if actions like the kind we've seen over the last few days continue, you're going to see a ramping up of those sanctions," Power said.
NATO Secretary-General Anders Fogh Rasmussen described the appearance in eastern Ukraine of men with specialized Russian weapons and identical uniforms, though without insignia, as a "grave development."
"Let's call this what it is: this is war," MEP Jacek Saryusz-Wolski told the TVN24 channel. (pg/ss)