Thousands of Egyptians supporting ousted President Mohamed Morsi have gathered in Cairo, praying and celebrating Eid al-Fitr at protest camps despite government warnings to vacate the sites.
Opponents of Mr. Morsi also gathered Thursday in Cairo's Tahrir Square, a day after interim President Adly Mansour said efforts by international envoys to bridge Egypt's political divide had failed.
Mr. Mansour blamed Mr. Morsi's Muslim Brotherhood for the failure.
The United States and European Union voiced their concerns, saying the political divide has created a fragile situation that could spark more bloodshed.
In a joint statement late Wednesday, U.S. Secretary of State John Kerry and EU foreign policy chief Catherine Ashton said the two sides must break a "dangerous stalemate" and implement "tangible confidence building measures."
The diplomats said Egypt's government bears a special responsibility to begin a reconciliation process.