New clashes erupted on Wednesday in Cairo between security forces and protesters angry at a decree by President Mohammed Morsi granting himself sweeping new powers, said witnesses.
Police fired tears gas against the stone-throwing protesters in Tahrir Square, where thousands have been camping out for several days in a bid to convince Mr Morsi to rescind the decree.
State television confirmed that police had used tear gas to disperse protesters who were gathering near the U.S. embassy.
Last week, Mr Morsi signed a constitutional declaration exempting all his decisions and laws of judicial review and barred courts from dissolving an Islamist-controlled assembly drafting a new constitution.