Defiant Buddhist monks banned from marking a key Tibetan New Year prayer festival marched in protest in China's southwest, rights groups said. It was the latest resistance to Chinese rule ahead of sensitive anniversaries in Tibet. Tensions are high over harsh security measures set up before the new year, which began Feb. 25. The Monlam prayer festival started on Saturday and ends on March 11. The usually merry atmosphere has been largely subdued since the Dalai Lama, Tibet's spiritual leader, said celebrations would be "inappropriate" after deadly anti-government riots in Tibet's capital, Lhasa, last March led to a crackdown on protesters in Lhasa and Tibetan communities throughout the region.