At least 51 people were killed in clashes across Egypt Sunday during violence between opponents and supporters of deposed president Mohamed Mursi.

Police fired tear gas at Mursi supporters in Cairo as they tried to march towards Tahrir Square.

Some supporters tried to flee in a boat, but ended up jumping into the Nile after police fired tear gas at the boat.

The country has been in the throws of turmoil since the army ousted Mursi in July after mass protests against his rule.

In a sign of more possible violence to come, an alliance including Mursi's Muslim Brotherhood urged Egyptians to protest from Tuesday and gather on Cairo's Tahrir Square on Friday