Egyptian police check the damage after an explosion at the Imbaba courthouse, on Tuesday in Cairo, Egypt.
Egyptians formed long lines outside polling stations to vote on a new constitution that represents a key milestone in a military-backed roadmap put in place after the ouster of Egypt's Islamist president in a coup last July.
The balloting deals a heavy blow to the Muslim Brotherhood's campaign for the reinstatement of ousted President Mohammed Morsi and paves the way for a likely presidential run by the nation's top general, Abdel-Fattah el-Sissi.