11.   Many became taxis on the northern roads between Mandalay and the Chinese border, stomping ground of hill tribes, smugglers and opium lords.

12.   Now a study of hill tribes in northern Thailand supports that explanation.

13.   Oil paintings depict generals making peace deals with ethnic insurgents and promoting development to end the dependence of hill tribes on opium as a crop.

14.   Tension between Thai narcotics police and the Hmong hill tribes has been building up in recent months as authorities have stepped up their activities to combat methamphetamine abuse.

15.   The hill tribes generally live off subsistence agriculture and handouts from backpacking tourists.

16.   The hill tribes living in the highland area of Inthanond are today normal Thai highlanders with as much citizenship right as the lowland Thais.

17.   Three of the victims were ethnic Vietnamese, while the rest were from minority hill tribes.

18.   Two of the three Vietnamese provinces hit earlier this year by hill tribe protests are responding positively by improving conditions for ethnic minorities, the U.S. ambassador said Wednesday.

19.   But, since the Hmong were a primarily illiterate hill tribe, learning English and US history, as required to become citizens, is inordinately difficult.

20.   Last year, Ea Hleo was at the centre of persistent protests by the hill tribes that inhabit the surrounding countryside.