A ranking Ukrainian Opposition Leader has feared a possible russian invasion of his country. Oleg Tyagnybok, the official leader of the legalized neo-Nazi party Svoboda (Freedom), which has a parliamentary faction in the Ukrainian parliament, has said he fears a russian military invasion , of course against Ukraine. Tyagnybok, who is one of the “troika” or the Big Three of Maidan’s leaders is probably the most noticeable one, further said :’ We do not rule out a military invasion on part of Russia . We got information that russian troops , particularly units of the marines are on their way to Sevastopol city, which is a city, seaport and railway station located in Crimea, southern Ukraine, in the southwestern part of Crimean Peninsula on the southern shore of the long, narrow Akhtiarskaya Bay, which forms a magnificent natural harbor. A Russian invasion of Ukraine would be a “grave mistake,” President Barack Obama’s National Security Adviser Susan Rice said on NBC’s Meet the Press on Sunday. Russia’s considerable interests in Ukraine fuel fears of an intervention. Deposed President Viktor Yanukovych backed out of a trade pact with Europe last year and instead turned to Russia, prompting the furious response from thousands of Ukrainians who eventually toppled his government.