Islamabad: Pakistan's Army Chief General Raheel Sharif on Thursday confirmed the death sentence of another 12 "hardcore terrorists", who were involved in heinous offences, the military said. An army statement said the terrorists were found guilty of "killing of civilians, attacking armed forces of Pakistan and law enforcement agencies, destruction of schools and communication infrastructure". These convicts were tried by military courts, a statement from the army's Inter-Services Public Relations said, according to Xinhua. The army said all the men had admitted their offences before the magistrates and the trial court. Eleven convicts belonged to the Tehreek-e-Taliban Pakistan and one to sectarian group Lashkar-e-Jhangvi. The army courts were set up after the terrorist attack on an army school in December 2014 for the speedy trial of the terrorism-related accused. The convicts have the right of appeal to the president under the law, according to the legal experts. The President has previously rejected all mercy petitions in terrorism-related cases. Prime Minister Nawaz Sharif had advised the President to reject all mercy petitions of the militants as they have been responsible for the killing of the security men and civilians. It is the second time in less than three months the army chief has confirmed the death penalty to the militants. On May 12, Gen Raheel Sharif had confirmed the death sentence of a group of five "hardcore terrorists."