An explosion rocked the heart of the Pakistani capital today and was followed by an exchange of fire between security forces and suspected militants near a crowded market place.
The blast occurred near the Jinnah supermarket in the centre of Islamabad, which was packed with shoppers.
Reports said the blast had occurred near a security check post. Several ambulances were seen taking injured persons away from the area.
The explosion was followed by an exchange of fire that was continuing.
Panicked shoppers rushed out of the supermarket causing traffic snarls on nearby roads.
Police and security personnel cordoned off the area.
The number of casualties is not yet known.