Egypt’s Muslim Brotherhood is calling for an uprising after government forces turned their weapons on brotherhood protesters and opened fire, killing at least 51 people.

This happened outside the barracks where protesters believe deposed former president Mohammed Morsi is being detained by the military.  Hundreds were injured, and were rushed to hospitals and mosques.  It’s the largest one-day death toll since Morsi was ousted.

Both sides claim the other shot first.  The Egyptian Military released a video apparently showing masked protesters shooting at the cops and pelting them with rocks.

Meanwhile, interim President Adly Mansour is outlining his plan to return Egypt to democracy.

First, a panel to amend the constitution will be convened within two weeks.  The Muslim Brotherhood wrote the suspended constitution, and critics say the document leans Islamist.

A referendum on the new constitution would take place within four months, paving the way to parliamentary elections as early as February.