A deadline issued by China's communist leaders for protesters involved in violent anti-government riots in Tibet to turn themselves in or face severe punishment passed Tuesday without any apparent surrenders or arrests. In the central government's first comment on last week's violence, Foreign Ministry spokesman Liu Jianchao blamed the violence in Lhasa on supporters of the Dalai Lama, the revered spiritual leader who fled in 1959 after a failed uprising against Chinese rule. "The Chinese government will unwaveringly protect its national sovereignty and territorial integrity," ministry spokesman Liu Jianchao said at a hastily called news conference on Monday night. "The violent acts have demonstrated the true nature of the Dalai clique." An official at the Administrative Department of the city's Communist Party office said the city was returning to normal.