More than 12 people were killed and several others injured by a gas blast in the port city of Karachi, Pakistan today. Police said, the explosion went off in a bank building in the Sher Shah area and social media and TV footage showed the two-floor structure’s windows and doors blown out, with documents scattered across a wide area. An adjacent filling station was also damaged due to the explosion.

Most of the casualties are reportedly customers and staff present inside the bank which was built on top of a covered sewage channel. Provincial police told Media that a bomb disposal squad is investigating, but apparently, the leakage of gas seems to be the cause.

Karachi, which is responsible for 60 percent of Pakistan’s economic output, has long endured creaky infrastructure, illegal construction, and failing municipal services.