At least 17 people were killed and dozens were injured after a gas pipeline reportedly exploded at a mosque in Bangladesh, officials said on Saturday.

“I saw smoke was belching out of the mosque after the sudden explosion with a big bang and people were screaming. Some were rolling on the street as they tried to put out the flames on their bodies,” said local resident Mohammad Ratan.

Fire officials said gas that accumulated from a leak in a pipeline running underneath the mosque likely triggered the explosion.

Read more: At least 95 killed as fierce cyclone hits India and Bangladesh

“We primarily suspect that gas leaked from the pipeline and accumulated inside since the windows were closed. The explosion was probably triggered due to sparks when the air conditioners were turned on,” said Abdullah Al Arefin, a senior fire service official.

Authorities have launched an investigation into the incident.

Lax regulations and poor enforcement are often blamed for domestic and industrial fires in Bangladesh.