China detains hundreds in Tibet over self-immolation protests Sunday's incident was the first of its kind in the Tibetan capital, which has been under tight security since deadly anti-Chinese government riots broke out there in 2008. Residents of Lhasa said the city was under even tighter security than usual following Sunday's protest, with police and paramilitary officers out in force. One resident contacted by AFP on Monday said police were carrying out identity checks in the streets and that mobile telephone signals had been blocked. Free Tibet, a London-based campaign group, also said it had received reports that Tibetan residents in Lhasa had been arbitrarily detained in the wake of the protest. More than 30 people have set themselves on fire in Tibetan-inhabited areas of China since the start of March 2011 in protest at what they say is religious and cultural repression by the Chinese authorities. Tibetans have long chafed under China's rule over the vast Tibetan plateau, saying that Beijing has curbed religious freedoms and their culture is being eroded by an influx of Han Chinese, the country's main ethnic group. Beijing insists that Tibetans enjoy religious freedom and have benefited from improved living standards brought on by China's economic expansion.