Egyptian president Mohamed Mursi has declared a 30-day state of emergency and a curfew in three Suez Canal cities.
He also called for dialogue with political forces to resolve the country's latest crisis, which has seen 45 people killed in violent scenes this weekend.
He said a curfew would be introduced in Port Said, Ismailia and Suez starting on Monday from 9:00pm (1900 GMT) to 6:00am (0400 GMT).
Wherever there is division in Egypt right now – death seems sure to follow. The greatest toll came amid gunfire and tear gas in Port Said.
Riots sparked by death sentences passed in connection with last year's deadly riot at the Port Said football stadium have killed 22 people.