Pakistan executed four men on Wednesday for involvement in the massacre of 134 children at an army-run school in the northwestern city of Peshawar last year, media and security sources said.

The hangings were the first executions of civilians convicted by Pakistan's military courts, which were set up after the massacre through a constitutional amendment.

The executions were confirmed by three security sources, two of whom are based in Kohat, where the men were hanged early in the morning at the city's civilian-run central jail.

Hazrat Ali, Mujeeb ur Rehman, Sabeel and Abdus Salam had been convicted on Aug. 13, according to a military statement sent on that date. All were identified as members of the Toheedwal Jihad Group (TWG), a previously unheard-of faction of the Pakistani Taliban.

Parents of children killed in the attack welcomed the executions and demanded that all those connected to the attack be given the same punishment.

"Today's executions cannot return my son to us, but I am happy to know that at least four terrorists have been hanged for their role in the killing of our children," said a woman who identified herself only as the wife of Arshad Zafar, in keeping with local custom.

She praised the military for trying, convicting and hanging them ahead of the anniversary of the Dec. 16, 2014 attack.

Malik Tahir Awan, who lost his son in the attack, said "all those who played any role in the attack on Army Public School should be hanged."

"Dec. 16 is not far away, and that was the day when I lost my son. I shall never be able to forget this pain," he told The Associated Press by phone.

Three others were also sentenced to death for involvement in the attack, according to the military statement, but death warrants have not yet been issued for them.

All nine attackers were killed in the siege on Peshawar's Army Public School, which killed 151 people in total. It was the worst Taliban attack on Pakistani soil.

With files from The Associated Press