The UN Secretary-General Ban Ki-moon strongly condemned a bus attack occurred in northern Pakistan, killing at least 15 innocent passengers and causing multiple injuries.In a statement released here by Ban's spokesperson, the UN chief strongly condemned the "appalling" attack."The Secretary-General expressed his outrage over such deliberate attacks on people due to their religious beliefs in Pakistan," said the statement. "He also extended his heartfelt condolences to the families of the victims and to the government and people of Pakistan."