Outside the closed gates of the Xilingol Mongolian high school, Chinese police watch warily as hundreds of students perform calisthenics in a yard from where the previous day they left to march through the streets.
A short drive away, another police unit monitors a middle school that has become a source of concern. Security forces in Inner Mongolia, an autonomous region of China , are on high alert after the biggest wave of demonstrations in 20 years, sparked by a killing that symbolises the traumatic transition of Mongolia's nomadic grasslands into a mining powerhouse. On 11 May, a Han Chinese coal-truck driver ran over a year-old Mongolian herder, known as Mergen, as he tried to stop a convoy driving across fenced prairies in Xiwu.
Allegations the killing was deliberate inflamed passions in the indigenous Mongolian community, which has been squeezed out of much of the land over 50 years. Protests erupted in at least three places. According to overseas groups, crowds also took to the streets in Huveet Shar on Thursday and Shuluun Huh on Friday with banners declaring: "Defend the rights of Mongols" and "Defend the homeland".
The biggest protest was in Xilinhot, where 1, students in yellow and blue uniforms marched through the broad streets to the government headquarters on Wednesday. In recent years, Inner Mongolia has become China's leading producer of coal and rare earth elements. Details of the killing that sparked the protests are sketchy, second-hand and may have been exaggerated by internet rumours and a lack of trust in censored official news. Locals said year-old Mergen was leading about 40 herders who tried to block a convoy of coal trucks from the Tongcheng No 2 colliery.
The drivers had reportedly run down fences and intruded on nomads' land to avoid a bumpy road. After a protracted stand-off, the drivers are said to have crashed through the herders, killing Mergen.
