CAIRO — Egyptian riot police beefed up security around the presidential palace Tuesday ahead of a massive rally planned by activists protesting the Islamist leader's assumption of nearly unrestricted powers and a draft constitution hurriedly adopted by his allies.

The march comes amid rising anger over the draft charter and decrees issued by Mohammed Morsi giving himself sweeping powers. Morsi called for a nationwide referendum on the draft constitution on Dec. 15.

It is Egypt's worst political crisis since the ouster nearly two years ago of authoritarian president Hosni Mubarak. The country has been divided into two camps: Morsi and his fundamentalist Muslim Brotherhood, as well as ultraconservative Salafi Islamists versus youth groups, liberal parties and large sectors of the public.