At least 20 people were killed Wednesday in Cairo and at least 160 injured in clashes when a group of armed “thugs” attacked protesters demanding an end to military rule. The violence came just weeks ahead of Egypt’s first post-Mubarak campaign, and resulted in two Islamist candidates suspending their campaigns. “Where is the Army? Why are they not stopping these people?” cried one bystander during the violence, which included unidentified men attacking protesters with batons and guns, with some protesters retaliating by beating their assailants. The military will hold a meeting Wednesday with political party leaders to defuse the violence, but Egypt’s largest political party, the Muslim Brotherhood, said it will boycott any meeting.