ISLAMABAD, Sept 1: A Pakistan Air Force (PAF) fighter aircraft broke the sound barrier on Wednesday causing a sonic boom that was heard in the twin cities of Rawalpindi and Islamabad.

A spokesman for the PAF, Air Commodore Sarfaraz Ahmed Khan, told Dawn that the sonic boom occurred at high attitude over Fateh jang. The F-7 fighter aircraft, which was on a training mission, landed back at PAF Minhas Air Base in Kamra.

The sonic boom, he said, created a loud bang on the ground which caused unnecessary alarm. Air Commodore Sarfaraz Ahmed said the fighter aircraft had taken off from the Minhas air base after a major technical inspection. The mission also included supersonic flight in the designated PAF flight training area, he added.

Meanwhile, the residents of the twin cities remained confused for several hours as they failed to know the cause of the bang, which occurred at around 2:10pm. The situation became more complex when the PAF authorities also denied that any aircraft had broken the sound barrier. However, later in the evening, the PAF confirmed the incident.

Soon after the explosion, the newspapers' offices started receiving phone calls from various parts of Rawalpindi and Islamabad. However, there were no reports of an explosion from any part of the twin cities and the reporters continued to find out the spot where the explosion might have taken place.

The police, city administration, security and other rescue agencies of Rawalpindi and Islamabad confirmed hearing the bang, but they could not say what had caused the blast and where it had occurred.

Emergency was also declared in the government hospitals of twin cities. The doctors, when contacted, said the hospital managements had told them that there were reports of seven to nine blasts in the city and a large number of causalities were expected.

Ambulances, doctors, paramedics and other rescue workers were put on high alert and a large number of blood bags and medicines had also been arranged to handle any emergency.