Police have arrested 70 people from China's minority Uighur ethnic group in the Silk Road oasis city of Kashgar, an exile group said today.
Local officials denied there had been arrests, but local residents said security has been tightened ahead of August's Beijing Games as authorities fear trouble when the Olympic torch passes through the city in June.
China is facing ethnic unrest on two fronts: In Xinjiang, protesters in one city last month rallied for more religious freedom, while in Tibet, Buddhist monk-led marches turned into an anti-Chinese riot in the capital Lhasa last month and touched off demonstrations in the region.
Today, an official Tibet news website said police had caught more than 800 people linked to the Lhasa violence and 280 people had turned themselves in.
The recent unrest has dented propaganda claims of harmony and cast a shadow over the Olympics, which the Chinese leadership has hoped will be a chance to showcase the country's development.
China has responded by cranking up security, sending thousands of troops into Tibetan-populated areas and undertaking a propaganda blitz.