Cairo: The death toll from the violence engulfing Egypt rose to more than 600, as supporters of ousted President Mohamed Morsi vowed to continue their protests despite a crackdown by the military-backed government.

At least 638 people were killed and 3,994 injured in clashes ignited on Wednesday when security forces broke up two sit-ins by protesters loyal to Morsi and his Muslim Brotherhood, according to a Health Ministry official. The dead, mostly Morsi supporters, include at least 43 police officers.

Violence spread on Thursday, with government buildings set afire near the pyramids, policemen gunned down and scores of Christian churches attacked. As turmoil engulfed the country, the Interior Ministry authorized the use of deadly force against protesters targeting police and state institutions.