Egyptian officials say calm has returned to the country with a nighttime curfew in force after riot police used armored vehicles and bulldozers to break up two large protest camps in Cairo.
The interim government says 278 people, including 43 policemen, were killed Wednesday.
But a spokesman for the Muslim Brotherhood, which demands ousted President Mohamed Morsi be returned 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 and field hospitals. 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.
Interior Minister Mohamed 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. He accuses it of 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.
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."