DHAKA: At least seven people were killed and another 25 injured after a gas pipeline exploded in southeastern Bangladesh on Sunday, police said.The explosion at Patharghata area in Chittagong district collapsed portions of a boundary wall of a nearby building, local police chief Mohammed Mohsin said. He said at least 25 people were hospitalized and firefighters joined the rescue operation.It was not immediately clear what caused the explosion. News reports said the road in front of the explosion site was busy with people and tricycle rickshaws. A boundary wall fell on the people on the road. The explosion took place when residents were preparing for the day’s work in the morning, Mohsin said.Chittagong is 216 kilometers (134 miles) southeast of the capital, Dhaka.