NEW DELHI, Sept. 13 (Xinhua) -- At least six people were killed and four others injured, two of them critically, after rocks caved in inside a stone quarry in the eastern Indian state of West Bengal, officials said Saturday.

The stretch of stone quarry collapsed on Friday near Bahadurpur village of Nalhati in Birbhum district.

Following the collapse, locals, police personnel and rescuers from the fire and emergency department rushed to the site to rescue workers trapped under the debris.

"Ten people were moved to Rampurhat Medical College and Hospital, where doctors declared six of them dead on arrival. The remaining four are undergoing treatment," the official said.

Local media reports quoting eyewitnesses said workers were removing stones when an explosion triggered a collapse of a large section of the quarry.

The heavy monsoon rain, which caused waterlogging in mines and loosened the earth, might have caused the collapse, reports said.

Police have registered a case and ordered an investigation into the incident. ■