Egypt's National Alliance to Support Legitimacy has renewed its calls for marches to Tahrir Square on Friday to protest "massacres against Egyptians," following deadly clashes on Sunday between security forces and protesters.

The group, a coalition of Islamist supporters of ousted president Mohamed Morsi, also called for student protests at schools and universities on Tuesday.

At least 53 protesters were killed on Sunday when clashes erupted in a number of governorates across Egypt. Most of the deaths occurred in Cairo when pro-Morsi marchers attempted to reach Tahrir Square, where thousands were celebrating the 40th anniversary of the 1973 war against Israel and voicing support for the army.

"[Tahrir] Square belongs to all Egyptians and no one will prevent us from demonstrating in it, no matter the sacrifices," said the coalition's statement, released on Sunday night.

Hundreds of Morsi supporters were killed in August when security forces forcibly dispersed two protest camps in Cairo. Following the dispersal, the country's interim government declared zero-tolerance against any attempts to build new sit-ins, and imposed a heavy security presence around the capital's major squares.