The United Nations joined Afghan President Hamid Karzai on Thursday in calling on the U.S. military to punish those who burned copies of the Qur'an at a NATO air base. 'After the first step of a profound apology, there must be a second step ... of disciplinary action,' Jan Kubis, the special representative for the U.N. secretary-general in Afghanistan, told reporters in Kabul. He called the incident a 'very unfortunate mistake ... very sad.'