CAIRO – Supporters and opponents of President Mohammed Morsi clashed Friday in the worst violence since he took office, while he defended a decision to give himself near-absolute power to root out what he called “weevils eating away at the nation of Egypt.”

The edicts by Morsi, which were issued Thursday, have turned months of growing polarization into an open battle between his Muslim Brotherhood and liberals who fear a new dictatorship. Some in the opposition, which has been divided and weakened, were now speaking of a sustained street campaign against the man who nearly five months ago became Egypt’s first freely elected president.

The unrest also underscored the struggle over the direction of Egypt’s turbulent passage nearly two years after a popular uprising toppled Hosni Mubarak’s authoritarian regime. Liberals and secular Egyptians accuse the Brotherhood of monopolizing power, dominating the writing of a new constitution and failing to tackle the country’s chronic economic and security problems.