CAIRO (AP) — Thousands of opponents of Egypt’s Islamist president clashed with his supporters in cities across the country Friday, burning several offices of the Muslim Brotherhood, in the most violent and widespread protests since Mohammed Morsi came to power, sparked by his move to grant himself sweeping powers.

The violence, which left 100 people injured, reflected the increasingly dangerous polarization in Egypt over what course it will take nearly two years after the fall of autocrat Hosni Mubarak.