CNN  — 

A gas explosion caused part of a coal mine to collapse Saturday in the Pakistani city of Quetta, killing at least 16 people, provincial disaster management agency chief Muhammad Tariq said.

Six people were rescued and taken to a hospital for treatment, and rescuers were still looking Saturday night for one person believed trapped in the mine, officials said.

Details about what led to the explosion weren’t immediately available.

Quetta is the provincial capital and largest city of western Pakistan’s Balochistan province.

CNN’s Jason Hanna contributed to this report.