U.N. Secretary-General Ban Ki-moon on Friday pleaded for Damascus to grant immediate access for aid workers to besieged Syrian towns, describing images of death in Syria as “atrocious.” Ban Ki-moon was speaking to reporters at U.N. headquarters after the International Committee of the Red Cross told Syria it was unacceptable that its aid convoy had been prevented from entering a devastated district of Homs where the opposition said the army had committed a massacre. “The images which we have seen in Syria [are] atrocious,” Ban said. “It's totally unacceptable, intolerable. How as a human being can you bear … this situation? That really troubles me. I'm deeply sad seeing what's happening.” In an unusual show of unity with Western powers, Russia and China joined other Security Council members Thursday to express “deep disappointment” at Syria's failure to allow U.N. humanitarian-aid chief Valerie Amos to visit the country and urged that she be allowed to enter immediately. “The Syrian authorities must open, without any preconditions, to humanitarian communities,” Ban Ki-moon said, echoing the Security Council statement. “Why are they afraid of receiving the head of the U.N. humanitarian department? We are ready to mobilize, we do not have access. So that is priority number one at this time. “All violence must stop,” the secretary-general declared. “I am really urging Syrian authorities stop [the] violence and allow humanitarian access.” The United Nations says Syrian security forces have killed more than 7,500 civilians during an 11-month government crackdown on pro-democracy protesters.