Another 444 people were injured in the clashes between Morsi's opponents and supporters, it added.

Morsi, who headed the Muslim Brotherhood's Freedom and Justice Party before becoming Egypt's first elected president, last week decreed that all his decisions and laws are immune to legal challenge and barred courts from dissolving the constituent assembly, drafting the country's new constitution.

The president was due to meet with the country's top judges to try to defuse the crisis over Thursday's decree. Morsi's office said Sunday that the constitutional declaration is temporary until the new constitution is approved.

A 15-year-old, identified as a Muslim Brotherhood member, was killed and 60 people injured in an attack late Sunday in the Nile Delta city of Damanhour on an office of the movement, which supports Morsi.

There were no details about the second death.

Hundreds of Egyptians, meanwhile, filled Tahrir Square Monday as they took part in a funeral procession of a man killed last week in clashes between police forces and protesters on the anniversary of clashes that took place last year in central Cairo.

Protesters began a sit-in in Tahrir Square three days ago and are planning a mass demonstration on Tuesday to protest Morsi's decree.

The US embassy, located just south of Tahrir Square, announced that it will close its visa and services offices on Tuesday due to "the security situation in the vicinity."