PESHAWAR, Pakistan: The militant commander accused of masterminding Pakistan's deadliest ever extremist attack, a massacre at a school in Peshawar in 2014, has been killed, the Pakistani Taliban said in an email to media Wednesday.

The message from the Tehreek-e-Taliban Pakistan (TTP), the umbrella group which forms the Pakistani Taliban, did not say when or where Umar Mansoor had been killed, and there was no immediate comment from the Pakistani military or government.

The Mansour-led faction of the TTP, the Tariq Gidar Group (TGG), had claimed responsibility for the attack on the school in Peshawar, in which more than 150 people were killed, most of them children.

The TGG, designated a terrorist group by the US, was also responsible for attack on a university in Charsadda in which 21 people were killed.

After both attacks, Mansoor issued videos vowing to target schools across Pakistan.

Grieving parents welcomed the news of Mansour's death.

"The entire world is happy over the killing of the mastermind" behind the Peshawar school assault, Tufail Khan Khattak, whose son was killed in the attack, told AFP.

Some reports had emerged in 2016 of Mansoor's death, but AFP was unable to confirm them with officials or the militants at the time.

The militants also announced that "Khalifa Usman Mansoor will replace him in Darra Adam Khel and Peshawar," TTP spokesman Mohammad Khurasani said in a statement.—AFP