CAIRO — The Egyptian army deployed tanks and gave both supporters and opponents of Mohammed Morsi a deadline to leave the area outside the presidential palace Thursday following fierce street battles 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 possible 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.

Opposition activists defiantly called for another protest outside the palace later Thursday, raising the specter of more bloodshed as neither side showed willingness to back down.