At least fifteen people were killed on Wednesday (March 15) when a bomb exploded on a bus carrying government officials in the northwest Pakistani frontier city of Peshawar, officials said.The attack took place on a main road after the bus picked up government employees from areas surrounding Peshawar and was transporting them to work in the city.Rescue workers arrived at the blast site soon after the blast explosion.Director of Operations for Rescue 1122, Dr. Mohammad Ayaz, told reporters they heard the blast in their office which is a short distance from where the blast occurred."As soon as we heard the sound (of blast), our personnel rushed out and came here in a vehicle. Initially, I can say, unofficially, that around 30 people are injured, but that number can be higher or lower. They have been shifted to the LRH (Lady Reading Hospital) and Cantt hospitals. Unofficially, I can say that around 15-16 persons were killed on the spot," Ayaz said.