China is placing increasing pressure on nearby countries like Pakistan, Thailand, Burma (and so on) to arrest and return Chinese Uighur Turks who show up illegally. China accuses these Uighurs of being Islamic terrorists. While a few are most are economic refugees fleeing Chinese oppression in their homeland that has the misfortune of being part of China. Northwest China has long been the home of the Uighur Turks but in the last few decades China has encouraged Han (ethnic Chinese) to migrate to the area (Xinjiang province). Most Uighurs are found in Xinjiang province. There the nine million Uighurs are now less than half the population and most of the rest are Han Chinese. Chinese officials have been publicly urging soldiers and police to be more aggressive against uncooperative Uighurs.
The Uighurs are increasingly aggressive in attacking the growing Chinese presence among them. In Xinjiang province what angers the Uighurs is growing pressure from Han Chinese soldiers and intrusive Han government officials. Because of that many Uighurs continue to support anti-Han activity and this makes it possible for Islamic terrorists to survive and operate. The government accuses Uighur activists of endangering state security and tries to keep the unrest out of the news. The same thing is happening in Tibet, where the government is using the same tools to keep everyone under control.
While China is obsessed with the few Islamic terrorists fleeing Xinjiang most of these Uighurs are simply fleeing China. Many are showing up in Turkey, via smugglers who specialize in getting Uighurs out and as far away from China as possible. Turkey refuses Chinese demands to return any of these Uighurs unless they are caught engaging in Islamic terrorist activities.