Poor intelligence and porous borders with Southeast Asia are stymieing China's efforts to stop the flow of ethnic minority Uighur Muslims heading to Turkey, where China says many of them end up fighting for Islamists in Syria and Iraq.
Hundreds, perhaps thousands, of Uighurs keen to escape strife in their far western Chinese homeland of Xinjiang have traveled clandestinely via Southeast Asia to Turkey.
Tong Bishan, a senior police officer who has been helping lead China's efforts to get the Uighurs back, said Saturday the Uighurs were mostly crossing into Vietnam and Laos.