At least 42 Morsi supporters were killed early Monday in Cairo and an estimated 300 injured, allegedly while at morning prayers at the Republican Guard compound—and the Muslim Brotherhood is calling for an uprising in response. The military blamed a “terrorist group” for the shooting and said that soldiers opened fire only after being provoked. “The protesters weren’t even looking,” said Muslim Brotherhood spokesman Gehad El-Haddad. “They had their heads bowed to the ground, and the police just started firing from one side, the Army from the other. And it was just chaos.” Meanwhile, Egypt’s ultra-conservative Islamic party, al-Nour, announced it would be withdrawing from talks to form an interim government after Monday’s shooting.