A Ukrainian serviceman holds a flag of Ukraine and smokes at a military base in the Crimean town of Belbek, near Sevastopol March 22, 2014. Russian troops have surrounded the Ukrainian airbase in Crimea and issued an ultimatum to forces inside to surrender, the deputy commander of the base in Belbek, near Sevastopol, said on Saturday. REUTERS/Shamil Zhumatov (UKRAINE – Tags: POLITICS MILITARY TPX IMAGES OF THE DAY) – RTR3I53X