Opponents of Egyptian President Mohamed Morsi began a one-week sit-in protest in Cairo's Tahrir Square on Friday to demand the Islamist leader retract a declaration that grants him broad powers.
"All revolutionary political forces have agreed to begin a sit-in starting Friday," the Popular Current led by former presidential candidate Hamdeen Sabbahi said in a statement, calling for a mass protest on Tuesday.
So far, 26 political movements and parties have agreed to take part in the sit-in, organisers told AFP.
On Thursday, Morsi assumed temporary sweeping powers, allowing him to issue laws and decrees that cannot be challenged by any court.
Supporters say the move will cut back a turbulent and seemingly endless transition to democracy, but outraged critics say he has now become a dictator.