An attack on anti-terrorist police headquarters in Pakistan's largest city, Karachi, has left 20 dead and at least 100 injured.
Police say they exchanged fire with militants trying to storm theCriminal Investigation Department building. Then a truck laden with explosives slammed into its boundary wall, detonated its load and almost completely destroyed the structure. The blast could be heard across several miles of the city of 14 million people.
Eyewitnesses said the blast left a crater 12 metres (40ft) wide in front of the gutted building in Pakistan's financial and commercial capital.TV footage showed bloodied victims being taken away on stretchers and dozens of security officers combing through the wreckage.