More than 20 independent and opposition newspapers in Egypt have suspended publication for a day to protest what they say is a government crackdown on press freedoms.
Editors and opposition party leaders called Sunday's one-day strike after the prosecution and jailing of seven journalists in September.
The charges ranged from misquoting Egypt's justice minister to spreading rumors about the health of President Hosni Mubarak and defaming his son Gamal.
The Bush administration said it was concerned about the prosecution of the Egyptian journalists.
Meanwhile, Bedouin tribesmen demanding better security from Egyptian authorities have attacked government buildings in the northern Sinai peninsula, in a protest triggered by a shooting attack by a rival clan.
At least six protesters were injured as they clashed with plainclothes police in the town of El-Arish Sunday. Authorities say a mob attacked the town council building and destroyed the local headquarters of the ruling party, torching furniture and pictures of President Hosni Mubarak.
Authorities say the unrest started Saturday after truckloads of armed men from one Bedouin clan entered El-Arish and fired at members of another clan. Police say one person was killed and at least three others were wounded.
Egyptian police used tear gas to try to quell the rioting that started after the shooting.