UNITED NATIONS: UN Secretary-General Ban Ki-moon strongly condemned on Tuesday a Taliban attack on a Pakistani school that left at least 141 dead, most of them students.

“It is an act of horror and rank cowardice to attack defenseless children while they learn,” Ban said at the start of a UN Security Council meeting.

“The hearts of the world go out to the parents and families who have lost loved ones.”

Taliban insurgents stormed the army-run school in Peshawar on Tuesday, going from classroom to classroom shooting children, some as young as 12, in one of Pakistan's bloodiest ever attacks.

Speaking in a solemn tone, Ban began his address to a council meeting on peacekeeping with the statement condemning what he termed the “blood-curdling attack” in Pakistan.

“I condemn this heinous attack in the strongest possible terms,” he said.

“No cause can justify such brutality. No grievance can excuse such horror. Schools must be safe and secure learning spaces. Getting an education is every child's right. Going to school should not be an act of bravery.”

Ban expressed UN support for the Pakistani government's efforts to fight terrorism and extremism, and urged Islamabad to make every effort to track down those responsible for the carnage.

The Tehreek-i-Taliban Pakistan (TTP) claimed responsibility for the attack, calling it revenge for a major military offensive in the region.

TTP spokesman Muhammad Khorasani said Tuesday's assault was carried out to avenge Taliban fighters and their families killed in the army's offensive against militant strongholds in North Waziristan. The military has hailed the operation as a major success in disrupting the TTP's insurgency.