BANGKOK, August 26 - Tensions between Burmese government troops and an armed ethnic group have sparked an exodus of thousands of people into China from northeastern Burma, activists and witnesses said on Wednesday.

Large groups crossed the border on Tuesday from Kokang in Burma’s Shan state, said a witness in Nansan, a town in China’s southern Yunnan province. About 10,000 people have fled Kokang since August 8, China’s Chongqing Evening News reported.