One person was killed and two are missing after explosives detonated prematurely at a sand quarry in southwest China's Yunnan Province, local authority said Monday.

The accident happened at about 11:05 a.m. at a quarry in Youyu Village, Luliang County on Sunday, a county government official said.

Another four people were injured, one seriously and were taken to hospital, he said.

The quarry was registered and fully licensed, he added.

Rescuers are clearing the 1.3 ton explosives still in a hole in the quarry and searching for the missing, he said.

Work safety officials from the Qujing city government and Luliang county are investigating the accident.

(Xinhua New Agency February 23, 2009)