CHENGDU -- One person has been killed and three others are trapped after a coal mine explosion in southwest China's Sichuan Province on Sunday.

The blast happened around 11 am at a coal mine in Xiaohe Township of Weiyuan County, when eight miners were carrying out a routine safety check, according to the county's information office.

Five miners were rescued, but one died on the way to hospital, while three others remain trapped.

The injured four are in a stable condition, according to the office.

An investigation into the cause of explosion is underway.

Weiyuan is about 200 kilometers from the provincial capital of Chengdu.