At least 20 teenagers were taken into custody by police in the remote western town of Hezuo on Wednesday, shortly after a larger group began a protest., a hotel clerk there said. The demonstrations appear to be the first unrest in tightly controlled Tibetan areas at a highly sensitive time. Historically Hezuo , surrounded by vast grasslands, is in one of the areas that was worst hit by famines and purges during the rule of Mao Zedong and foreigners have only been allowed to visit since 1999.