The Dalai Lama has said that an estimated 4,000 people who were imprisoned during anti-Chinese riots in Tibet last year remain in custody,and he called for an international investigation of the violence. The exiled Tibetan spiritual leader said yesterday that he remains encouraged by the growing solidarity and support Chinese people and intellectuals are showing for the Tibetan cause. But he said the situation in the region remains tense,despite having calmed since last years unrest and crackdown by the Chinese government. The anti-Chinese riots erupted in Lhasa in March 2008 and spread across western China. In response,Beijing poured troops into Tibetan areas,kept foreign media and tourists out,and purged Buddhist monasteries at the center of anti-government sentiment. China also intensified its vilification campaign against the Dalai Lama,accusing him of instigating the unrest. Im appealing to the international community go there and thoroughly investigate, the 74-year-old Nobel Peace Prize laureate said. The Chinese government should refrain from using force in dealing with Tibetans,the Dalai Lama said. He also expressed dismay that Tibetans were prohibited from using their own language.