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

United Nations Secretary-General Ban Ki-moon led a chorus of international condemnations of the “blood-curdling attack” on an Army-run school in Peshawar, as he backed calls for Pakistan to bring the perpetrators to justice.

The UN chief chose the Security Council to voice his outrage over the atrocity as the 15-member body met in an open meeting to discuss cooperation with regional organisations.  “It is an act of horror and rank cowardice to attack defenceless children while they learn, Ban said.

US President Barack Obama, Secretary of State John Kerry and other world leaders also joined in condemning the “horrific” attack. In his statement, the UN chief said, “The hearts of the world go out to the parents and families who lost loved ones in the horrific attack.” Stressing that the UN would continue to support the Government of Pakistan in its fight against terror and extremism and urging the govt to bring the perpetrators to justice, he said “no cause could justify such brutality.” President Obama said, “By targeting students and teachers in this heinous attack, terrorists have once again shown their depravity.

“We stand with the people of Pakistan, and reiterate the commitment of the United States to support the Government of Pakistan in its efforts to combat terrorism and extremism and to promote peace and stability in the region,” Obama added.

“The United States condemns in the strongest possible terms Tuesday’s horrific attack on the Army Public School in Peshawar, Pakistan. Our hearts and prayers go out to the victims, their families, and loved ones,” the US President said.

On his part, Kerry said, “Wherever you live, wherever you are, those are our children, and this is the world’s loss. This act of terror angers and shakes all people of conscience, and we condemn it in the strongest terms possible. “The perpetrators must be brought to justice. And we pledge our full support to the people of Pakistan in this difficult hour and we will help them in any way that we possibly can,” he said in London, according to a transcript of the remarks released by the State Department.

He termed the news of the brazen murder of innocent students in Peshawar as “devastating.”

“And as a father, I know exactly how hard it is when you send kids out of house into the world, to school or anywhere, and particularly in today’s world. Mothers and fathers send their kids to school to learn and to be safe and to dream and to find opportunity. And particularly at this military school in Pakistan, they sent their kids there with the hope and dreams of serving their country - And Prime Minister (Nawaz) Sharif said, ‘These are my children. It is my loss’.”

Kerry said he is confident that the Pakistanis are tough, strong and determined in their struggle.

Chairman Senate Foreign Relations Committee Robert Menendez, a Democrat from New Jersey, condemned in the strongest and most forceful of terms Tuesday’s attack targeting innocent children.

“Pakistan is grieving today and we in the United States mourn alongside the families who have lost their loved ones at the Army Public School in Peshawar.” Senior officials from across the UN system echoed the Secretary-General’s comments, with UN High Commissioner for Human Rights, Zeid Ra’ad Al Hussein, also condemning “an utterly despicable and incomprehensibly vicious attack on defenceless children.”

“The Taliban have sunk to an all-time depth with this attack,” Zeid said. “Everyone must now unite to combat this type of savage extremism. No Government or intelligence agencies, no religious figures, no wealthy sponsors, no members of the general public can possibly justify continuing support for the Taliban, ISIL, Boko Haram, al Qaeda or any of these takfiri groups which appear to be competing to attain the highest level of human barbarity.”

UN Educational, Scientific and Cultural Organisation (UNESCO) Director-General, Irina Bokova condemned the attack as “a crime against the future of all children and the nation of Pakistan” and “against learning and innocence”.

The Executive Director of the UN Children’s Fund (UNICEF), Tony Lake, called the attack “horrific” and “callous” and said it should have more effect than merely to shock the conscience of the world.

British Prime Minister David Cameron described the attack on the school as ‘deeply shocking’.

In a statement, French President Francois Hollande said “No words can express the ignominy of such an attack against children in their school. France ‘supported the government of Pakistan in their fight against terrorism’ and expressed solidarity with the victims and their parents.”

“The killing of innocent children is contrary to Islam,” Afghan President Ashraf Ghani said in a statement. “I condemn this criminal attack in the sharpest possible terms. The cruel cowardice of taking children hostage and murdering them surpasses everything that Pakistan, which has been subjected to terrorism and violence for years, has known to date,” German Foreign Minister Frank-Walter Steinmeier said.

“There can be absolutely no justification for targeting children in this way. This unconscionable Taliban attack is a grave reminder that civilians in north-west Pakistan desperately need effective protection from militant groups,” David Griffiths, Amnesty International’s Deputy Director for Asia-Pacific, said in a statement.

Chinese Foreign Ministry spokesman, while strongly condemning the terrorist attack on a school in Peshawar, has said that China opposes all forms of terrorism and will continue to render firm support to the government and people of Pakistan in the fight against terrorism and unremitting efforts in maintaining national stability and public safety. In a statement issued by the Chinese Embassy in Islamabad, the spokesperson said, “We are deeply shocked and saddened by the incident, and most strongly condemn the terrorist attack.” He said that China expresses profound condolences to the deceased and sincere sympathy to the injured and families of the deceased.