Three primary school children died after being buried by sand and rocks while searching for jade at a pit in northwest China's Xinjiang Uygur Autonomous Region, police said on Wednesday.

The children went missing on Sunday afternoon and their families reported their disappearance to police in Langru town, Hotan county, on Monday morning.

After receiving reports that the students carried shovels when leaving home, the police on Monday searched places around the town where people hunted for jade and found a sand and rock collapse in a pit left by an excavator.

The police found the bodies and confirmed after investigation that the children were killed by the collapse.

Details on the ages and gender of the children were unavailable.

Xinjiang produces up to 300 tons of Hotan Jade a year, 20 percent of which is pure white nephrite. A kilogram of white Hotan Jade can sell for more than 100,000 yuan (12,500 U.S. dollars), and prices have been rocketing because of a sharp decrease in output.

Lured by the possibility of fast money, jade hunters from all over the country swarm around the the river bed of the Yurungkax River during summer before the river freezes over in autumn.

(Xinhua News Agency December 13, 2007)