Egyptian Interior Minister Mohamed Ibrahim says 149 people were killed Wednesday when security forces used armored vehicles and bulldozers to break up two large protest camps in Cairo.
But a spokesman for the Muslim Brotherhood, which demands the return of ousted President Mohamed Morsi to power, says 2,600 people were killed when police fired into crowds of demonstrators with automatic rifles.
Witnesses and journalists report seeing bodies in makeshift morgues in Cairo. Islamists also rioted in Alexandria, Minya, Assiut and Suez as anger over the crackdown spread.
The government had warned for several days that it would move against the protesters -- most of whom also support Mr. Morsi.
Ibrahim says police used minimum force against the camps and only fired tear gas. He blames the Muslim Brotherhood for creating what he calls a state of mayhem across the country, including shooting at police, attacking government buildings, and burning churches.
Ibrahim says the interim government is heeding the call of the people to bring stability back to Egypt.
But interim vice president and pro-reform leader Mohamed ElBaradei resigned. He said he is not prepared to be held responsible for even "a single drop of blood."
Egypt's interim presidency announced a one-month state of emergency had begun and ordered the army to help the Interior Ministry enforce security. The government imposed a nighttime curfew in Cairo and several provinces.
Egypt's railway authority has suspended train service in and out of Cairo to keep activists from regrouping elsewhere.
SPOKESMAN FOR EGYPTIAN INTERIM PRIME MINISTER :
"The government demands the political leadership of the Brotherhood stop incitements to violence and holds these leaders fully responsible for any blood that is shed. The government also salutes the efforts of the security services for...using the utmost self-restraint and highest degree of professionalism in the operation to clear the sit-in."