Islamabad: Pakistan's army chief General Raheel Sharif on Tuesday confirmed the death sentence for another 13 "hardcore terrorists" who were involved in heinous offences related to terrorism. The convicts, who belonged to the outlawed Tehrik-e-Taliban Pakistan, were tried by military courts, an army statement said. A convict, Irfanullah, was behind the killing of 10 foreign tourists in the country's northern areas in 2013. The other convicts were involved in attacks at the airport in northwestern Swat valley, destruction of schools, attacks on armed forces, law enforcement agencies and civilians, said a statement from the army's Inter-Services Intelligence. The statement said all convicts confessed to their crimes. The army courts were set up after the terrorist attack on an army school in December 2014 for the speedy trial of terrorism accused.