The death toll in the military crackdown on protesters in Egypt had reached 638 by Thursday night, the Egyptian health ministry said.
Clashes between security forces and protesters including supporters of ousted President Mohammed Morsi on Wednesday left about 4,000 injured, according to the ministry.
The clashes prompted the government to declare a one-month state of emergency for the entire country and impose a curfew in Cairo and elsewhere.
A total of 288 people were confirmed dead in Cairo's Nasr City district where security forces stormed camps of protesters, while 90 died at a sit-in camp near the Cairo University campus.
Amid the continuing violence in the country, the interior ministry on Thursday warned of the use of live ammunition against attacks on public facilities and security forces.
Vice president and Nobel peace laureate Mohamed ElBaradei, who had opposed the forcible removal of protesters, resigned in protest.
The protesters were calling for Morsi's reinstatement after the military ousted Egypt's first democratically elected president on July 3.