Ukraine's interim president promised military action if government buildings were not given up by 06:00 GMT.But correspondents said the Russian flag was still flying over the police station seized in Sloviansk.Clashes with pro-Russian gunmen on the outskirts of the city on Sunday left at least one Ukrainian officer dead.At an emergency meeting of the UN Security Council on Sunday, Russia urged Kiev not to use force against protesters in eastern Ukraine.The Russian Ambassador to the UN, Vitaliy Churkin, called on the government in Kiev to "start a genuine dialogue".But Ukraine's UN ambassador Yuriy Sergeyev said Moscow had artificially created the crisis in the east of the country.Ukraine's foreign ministry said Monday that it had proof Russian forces had been behind the "separatist operation" and said it would present its evidence at a meeting in Geneva later this week.Kiev had promised military action if pro-Russians failed to leave buildings they are occupying in Sloviansk and several other towns and cities.People in eastern Ukraine are now waiting to see if interim president Olexander Turchynov uses the army to try to take back control of the buildings.On Sunday, he said his military forces would launch a "full-scale anti-terrorist operation" against the armed men holding the buildings.The assistant UN Secretary General had warned that Ukraine "teeters on the brink".The BBC's Daniel Sandford in Donetsk says this could prove a critical day in eastern Ukraine - but that such deadlines have come and gone before.The new administration in Kiev is struggling for credibility in the east of the country and several towns and cities were effectively taken over by pro-Russian groups over the weekend.Sloviansk, in the Donetsk region, is completely surrounded by rebel barricades and checkpoints manned by pro-Russian militia are stationed on major roads leading into the city.Although Kiev has promised to take back control of Sloviansk, an all-out assault carries huge risks and could trigger a reaction from Russia, which has tens of thousands of troops camped near its border with Ukraine.'Spreading fiction'Russian Ambassador to the UN, Vitaliy Churkin, told an emergency meeting of the UN Security Council that there were neo-Nazis and anti-Semites within the ranks of "the self-proclaimed government in Kiev".He said the opinions and interests of protesters in eastern Ukraine had not been taken into consideration."The henchmen of Maidan [protest movement] must stop attacking their own people," said Mr Churkin.European Union foreign ministers are due to meet later on Monday in Luxembourg to discuss the crisis.The US said Russia was "spreading fiction" and that the events of the past week mirrored those preceding the annexation of Crimea."We know who is behind this," said Samantha Power, the United States' permanent representative to the UN.She said that the US would still take part in talks on the crisis planned for Geneva on Thursday.However, she said that if the talks were to succeed, Russia would have to explain the build-up of 40,000 troops on Ukraine's eastern border.It was the 10th time the Security Council has convened to discuss the Ukraine crisis.President Turchynov said he would not allow a repetition in the east of what happened in Crimea, which was annexed by Russia last month.Eastern Ukraine has a large Russian-speaking population and has seen a series of protests since the ousting of Ukraine's pro-Russian President Viktor Yanukovych in February.(BBC)ANN.Az