At least seven people died, and 25 others were injured after a gas pipeline exploded in southeast Bangladesh's port city, Chittagong, a police official said on Sunday.

The explosion at Patharghata area in Chittagong district collapsed portions of a boundary wall of a nearby building, local police official Mohammad Mohsin said. 

Officials believed that a gas leak-triggered explosion might have caused the incident.

The injured have been taken to hospital, and a rescue operation was underway.