On 14 August, the interim government declared a month-long state of emergency, and riot police cleared the pro-Morsi sit-in during the Rabaa sit-in dispersal of August 2013. Violence escalated rapidly following armed protesters attacking police, according to the National Council for Human Rights' report; this led to the deaths of over 600 people and injury of some 4,000, with the incident resulting in the most casualties in Egypt's modern history. In retaliation, Brotherhood supporters looted and burned police stations and dozens of churches in response to the violence, though a Muslim Brotherhood spokesperson condemned the attacks on Christians and instead blamed military leaders for plotting the attacks. The crackdown that followed has been called the worst for the Brotherhood's organization "in eight decades". By 19 August, Al Jazeera reported that "most" of the Brotherhood's leaders were in custody. On that day Supreme Leader Mohammed Badie was arrested, crossing a "red line", as even Hosni Mubarak had never arrested him. On 23 September, a court ordered the group outlawed and its assets seized. Prime Minister, Hazem Al Beblawi on 21 December 2013, declared the Muslim Brotherhood as a terrorist organisation after a car bomb ripped through a police building and killed at least 14 people in the city of Mansoura, which the government blamed on the Muslim Brotherhood, despite no evidence and an unaffiliated Sinai-based terror group claiming responsibility for the attack.