UN human rights chief Navi Pillay has condemned the "clearly excessive use of force" by Egypt's security forces during clashes with protesters.
Ms Pillay called for an independent inquiry into the deaths of at least 35 people since the weekend.
Protesters are still occupying Cairo's Tahrir Square despite the pledge of a speedier handover to civilian rule.
Security forces again fired tear gas at protesters near the interior ministry after a brief truce collapsed.
Marco Werman gets the latest from The World's Matthew Bell in Cairo.