An Egyptian security official says supporters of Egypt's ousted president Mohammed Morsi are clashing with opponents holding a sit-in in Cairo's Tahrir square.
Today's violence took place when several hundred pro-Morsi protesters were marching toward the US Embassy to hold a demonstration against alleged American meddling in Egypt's affairs, the official said.
The march passed an entrance to Tahrir Square manned by anti-Morsi protesters, and the two sides pelted each other with rocks. Gunfire was heard, but it was not clear who was firing.
Armoured vehicles moved and blocked the road, the official said, speaking on condition of anonymity because he was not authorised to speak to the press.
The Muslim Brotherhood has staged daily protests across the country since Morsi was deposed on July 3, demanding his reinstatement.
