A Chinese flag flies from a mast as Chinese riot police wearing padding and helmets and holding batons, shields and long sticks, perform drills in front of a commanding officer on basketball courts at a barracks located in the outskirts of Kangding in Sichuan province February 24, 2009. Kangding, a town in southwestern Sichuan province historically part of Tibet and heavily populated by Tibetans, is preparing to mark the Tibetan new year on February 25 amid heavy security, but this year's anniversary is extra sensitive as 2009 also marks the 50th anniversary of the flight into exile of Tibet's spiritual leader, the Dalai Lama, after an abortive uprising against Chinese rule.