Pakistan said Wednesday that Iran launched an airstrike on its territory that killed two children, after Tehran launched attacks in Iraq and Syria against what it called "anti-Iranian terrorist groups."

Pakistan denounced the strike, near the nation's shared border late on Tuesday, as "completely unacceptable," saying that it was unprovoked.

Iran offered no official comment immediately but its state-run Nour News agency said the attack destroyed the Pakistani headquarters of the jihadist group Jaish al-Adl (Army of Justice).