A Russian soldier looks through the sights of his weapon as Ukrainian servicemen wait at Belbek airport in the Crimea region March 4, 2014. REUTERS/Baz Ratner VIENNA (Reuters) - Warning shots were fired when an unarmed OSCE military observer mission was turned back while trying to cross into Ukraine's Crimea region on Saturday, the European security body said.

Nobody was from the mission was hurt. It was the third straight day that the mission from the Organization for Security and Cooperation in Europe had been turned back while trying to cross the narrow isthmus connecting the isolated Black Sea peninsula to the rest of Ukraine.

An OSCE spokeswoman said in an e-mail that the mission was withdrawing to the nearest big city, Kherson, to decide on its next steps. The mission has been invited by Ukraine's government, but the Russian separatist authorities in Crimea say they have not given it permission to enter the region.

Russian forces seized control of the region last week and President Vladimir Putin declared that Moscowhas the right to invade Ukraine to protect Russians there. Moscow says it has not sent troops beyond those of its Black Sea fleet normally based there, an assertion Washington has branded "Putin's fiction".

(Reporting by Georgina Prodhan; Writing by Peter Graff, Editing by Timothy Heritage)