Pro-Russia protesters who broke into a state security building in the eastern Ukrainian city of Lugansk have seized weapons, local police said on Monday.Road police closed down entrances into the city and were on alert, the Lugansk regional police office said.Separately, Interior Minister Arsen Avakov said on his Facebook page that the regional administrative building in another eastern city, Kharkov, had been cleared of protesters and that public employees had returned to work. Avakov said he was in the city.Pro-Russia protesters also broke into a regional administrative building in the mining city of Donetsk on Sunday. The demonstrators there raised the Russian flag atop the building and demanded the release of riot police accused of killing protesters in the Ukrainian capital of Kiev in February.Police were negotiating with the demonstrators, who have called for supporters to rally around the Regional Security Administration building in Donetsk, about 200 kilometers (120 miles) from the Russian border. Video of the negotiations was being streamed live online by local news outlets.The protests were the latest challenge to Ukraine's embattled new government, which took power after three months of demonstrations ousted pro-Russian President Viktor Yanukovych in February.They also come weeks after Russia annexed the Black Sea peninsula of Crimea from Ukraine, following a local referendum deemed illegal by Kiev and the West.On Sunday, a Russian soldier shot dead a Ukrainian navy officer in a officer's dorm in Novofedorivka in Crimea, Ukraine's defense ministry said in a statement posted on its website. The Ukrainian officer was getting ready to leave for mainland Ukraine from the Black Sea peninsula."Political tourists"Sunday's protests led Ukraine's acting President Oleksandr Turchinov to cancel a trip to Lithuania, his spokesman said. Turchinov, who also serves as parliament speaker, was scheduled to travel there to meet with speakers from European Union states.Turchinov will instead meet with law enforcement chiefs and take "personal control" of the response to the protests, the spokesman said.Ukrainian Prime Minister Arseniy Yatsenyuk announced on live television Sunday evening that he would travel to his country's eastern regions "to dismiss their fears."Yatsenyuk said he would offer to decentralize power and give state financial support for local businesses.In mid-March, Kiev's new government warned that pro-Russia forces in other regions might attempt to follow the model used to wrest Crimea from Ukraine.Yatsenyuk said demonstrations by what he called "political tourists" with foreign passports were already under way; Andrii Parubii, the secretary of the Ukrainian parliament's National Security and Defense Council, said protesters included "elite special units that are trying to arrive to Ukraine with weapons."(CNN)ANN.Az