Ashraf Chakar Irani , aged 30, was hanged in a Karachi jail early on Thursday.

He had been convicted of killing a policeman by one of the new military courts in the city. President Rafiq Tarar had rejected his appeal for mercy.

Owen Bennett-Jones in Islamabad: PM Sharif wanted speedier justice as a deterrent against Karachi's violence

The hanging took place amid tight security at the central prison in Karachi. The body was then handed over to relatives for burial.

The military courts were set up to crack down on spiralling ethnic, political and religious violence and crime in Karachi. They were told to complete trials in three days, with another three allowed for an appeal. In the event this case lasted a total of 12 days.

The setting up of the courts was controversial. The BBC Correspondent in Islamabad, Owen Bennett-Jones, says the government argued that it had to take drastic measures to reduce the high levels of crime in the city.