"I condemn this heinous act in the strongest possible terms. No cause can justify such brutality. No grievance can excuse such horror. It is an act of horror and rank cowardice to attack defenseless children while they learn. Schools must be safe and secure learning spaces. Getting an education is every child's right. Going to school should not have to be an act of bravery," Ban said.
Ban also offered condolences to the people and government in Pakistan, noting that the United Nations would be beside the Pakistani authorities and would help them fight against terrorism and extremism.
The UN Secretary-General also called on the government of Pakistan to hold to account those responsible for the brutal attack.
On Tuesday, a school in Pakistan's Peshawar city witnessed a suicide attack by six Taliban gunmen. The attack resulted in the deaths of around 130 people, most of them children. According to media reports, the terror attack was to take reprisal for the recent advancement of Pakistan's armed forces against the extremist group.