Armed men, believed to be Russian servicemen, stand guard at a military airbase in the Crimean town of Belbek near Sevastopol March 22, 2014. Russian troops forced their way into a Ukrainian airbase in Crimea with armored vehicles, automatic fire and stun grenades on Saturday, injuring a Ukrainian serviceman and detaining the base’s commander for talks. REUTERS/Shamil Zhumatov (UKRAINE – Tags: POLITICS MILITARY) – RTR3I5S6