Soldiers of frontier defence watch as China's national flag flies at half-mast in the Dai Ethnic Autonomous Prefecture of Xishuangbanna, southwest China's Yunnan Province, May 19, 2008. China on Monday begins a three-day national mourning for the tens of thousands of people killed in a powerful earthquake which struck the country's southwestern regions on May 12.

China's national flag flies at half-mast at people's square in Guiyang, southwest China's Guizhou Province, May 19, 2008. China on Monday begins a three-day national mourning for the tens of thousands of people killed in a powerful earthquake which struck the country's southwestern regions on May 12.

China's national flag flies at half-mast in front of the Potala Palace in Lhasa, southwest China's Tibet Autonomous Region, May 19, 2008. China on Monday begins a three-day national mourning for the tens of thousands of people killed in a powerful earthquake which struck the country's southwestern regions on May 12.

(Xinhua News Agency May 19, 2008)