The Egyptian army deployed tanks outside the presidential palace Thursday following fierce street battles between supporters and opponents of Mohammed Morsi that left five people dead and more than 600 injured in the worst outbreak of violence between the two sides since the Islamist leader's election.

The intensity of the overnight violence, with Morsi's Islamist backers and largely secular protesters lobbing firebombs and rocks at each other, signaled a turning point in the 2-week-old crisis over the president's assumption of near-absolute powers and the hurried adoption of a draft constitution.