The UN Secretary General Ban Ki-moon has appealed for an end to the violence in Libya, Egypt and Yemen, as further demonstrations over a US made anti-Muslim film were expected across the region after Friday prayers. In a statement issued by the U.N. press office ahead of Friday prayers and further planned demonstrations in some Muslim nations, Ban reiterated his condemnation of the attack that killed U.S. Ambassador to Libya Christopher Stevens and three other Americas in Benghazi on Tuesday. He \"calls for calm and restraint, and stresses the need for dialogue,\" stressing that \"nothing justifies such killings and attacks,\" it added. Clashes outside US missions on Thursday left four demonstrators dead in Yemen, and more than 200 injured in Cairo. Further demonstrations were expected after Friday prayers.