ISLAMABAD: World leaders Tuesday condemned the Taleban massacre of Pakistani schoolchildren as “heinous” and “an act of horror” in an outpouring of global revulsion at the attack which killed 141 people.

“We are deeply shocked and grieved by the attack and condemn in the strongest terms the terrorists,” Chinese Foreign Ministry said in a statement.

The assault was “one of the most shocking Taleban attacks in recent memory,” said rights group Amnesty International.

The Organization of Islamic Cooperation denounced the attack as “heinous.” “The OIC rejects all forms of terrorism,” said Iyad Madani, secretary-general of the 57-member group. “These terrorists who use Islam as a cover do not represent this divine religion at all,” he added.

Turkish Premier Ahmet Davutoglu said Turkey would observe one day of national mourning on Wednesday, while French President Francois Hollande described the attack as “vile.”

Italian Foreign Minister Paolo Gentiloni said: “The slaughter of children in Peshawar is a crime against humanity.”

Prime Minister Nawaz Sharif said: “We will avenge every single drop of our children’s blood.”

Pakistan Tehreek-e-Insaf chief Imran Khan said he would attend an urgent meeting convened by the premier to discuss the crisis.

Indian Premier Narendra Modi called Sharif to convey his condolences.