Adds info on hunger strike, Suez developments (first version posted at 12:37)
Thousands of Egyptians Saturday began an open-ended protest in Cairo and other big cities, threatening further action unless the country's military rulers expedite the prosecution of former government officials, dpa reported.
"We give the country's rulers until Sunday night to declare public, real and swift trials for the officials of the toppled regime and the killers of martyrs," the Second Revolution of Rage protest group said on its Facebook page.
"If not, there will be further measures, including a call for civil disobedience," the group wrote.
The protesters are disappointed at the slow pace of judicial proceedings against former president Hosny Mubarak and other officials.
An activist of the April 6 campaign group went on hunger strike in Alexandria, Egypt's second biggest city, to protest what the group considers the authorities' disregard of the "revolution's demands."
Other activists in Cairo and the coastal city of Port Said announced plans to go on hunger strike if their demands were not met.
Meanwhile, Interior Minister Mansour al-Essawi sacked the security chief in Suez, a restive city east of Cairo, for alleged involvement in aiding the escape of colleagues charged with killing protesters.
Suez has been the scene of violent clashes between police and families of slain protesters in the past few days.
On Friday, Egypt saw mass nationwide protests demanding that former officials - believed to be implicated in a deadly crackdown on demonstrators during the anti-Mubarak revolt - be tried quickly and in public.
The protesters are also pushing for state institutions, mainly the police, to be purged of those deemed loyal to Mubarak.
At least 846 people were killed and more than 6,000 injured in the uprising, according to a fact-finding commission.