A man carries an Egyptian police officer to an ambulance after Friday's blast at the Egyptian police headquarters in downtown Cairo. Khalil Hamra/AP hide caption

itoggle caption Khalil Hamra/AP

A man in Cairo who said he had been wounded by a rubber bullet Friday gets help. Andre Pain /EPA/LANDOV hide caption

itoggle caption Andre Pain /EPA/LANDOV

President Obama, speaking Thursday from the island of Martha's Vineyard, Mass., said the U.S. has canceled joint military exercises with Egypt. Jacquelyn Martin/AP hide caption

itoggle caption Jacquelyn Martin/AP

Posters of ousted Egyptian President Mohammed Morsi lay amid the rubble of a protest camp in Cairo after Wednesday's crackdown by government forces. Ahmed Assadi/EPA/Landov hide caption

itoggle caption Ahmed Assadi/EPA/Landov

Egyptian President Mohammed Morsi held a "dialogue" in Cairo on Saturday. Overnight, an official announced the president would nullify a decree that gave him expanded powers. Maya Alleruzzo/AP hide caption

itoggle caption Maya Alleruzzo/AP

Protesters gather in Tahrir Square in Cairo, Egypt, on Tuesday. Tens of thousands of Egyptians also gathered outside the presidential palace in Cairo in demonstrations that turned violent as tensions grew over President Mohammed Morsi's seizure of nearly unrestricted powers. Maya Alleruzzo/AP hide caption

itoggle caption Maya Alleruzzo/AP