A U.S. airstrike near Afghanistan‘s border with Pakistan killed the mastermind of a 2014 attack on a Pakistani school that killed some 150 people, mainly children, American and Pakistani officials said Wednesday.

Pentagon press secretary Peter Cook said the airstrike Saturday killed “known terrorist leader” Umar Khalifa, who was known by several other names including Khalifa Umar Mansoor. Cook said he was killed along with four other “enemy combatants” in an airstrike targeting members of an Islamic State affiliate known as Khorasan Province.

Cook said the attack was conducted in Nangarhar province, where the Islamic State has established a foothold. He called Khalifa a leader in the Tariq Gidar Group, which the State Department on May 25 designated as a global terrorist group. It said the group is linked to the Pakistani Taliban and is based in Dara Adam Khiel, Pakistan.

“Khalifa orchestrated multiple terrorist operations in Pakistan to include the January 2016 attack on Bacha Khan University, the September 2015 Badaber Air Force Base attack, and the December 2014 Peshawar school attack that resulted in the deaths of more than 130 children,” Cook said in a written statement.