At least 18 people have died in the protests across Egypt, hospital spokesmen told Efe Monday.
Nine people were killed in clashes between opposition members and Islamists at the Muslim Brotherhood's headquarters in Cairo.
A total of 716 people have been wounded in the protests, which started peacefully on Sunday and turned violent after nightfall.
Protesters demanding that President Mohammed Mursi step down attacked the headquarters of the Muslim Brotherhood, which the head of state belonged to until he took office, with Molotov cocktails and stones.
Muslim Brotherhood members fired shots at the protesters from inside the building, which the mob eventually took and burned.
The anti-Mursi protests continued on Monday, with hundreds of people occupying Tahrir Square and giving Mursi until Tuesday to resign.
Another wave of protests is expected to start at 4:00 p.m. on Monday. EFE