At least 20 people have been killed in Cairo in an attack on a protest near the Egyptian Ministry of Defence.
The unknown attackers used rocks, clubs, firebombs and shotguns. The protesters retaliated, beating some assailants.
Soldiers and police have now intervened to stop the clashes, but as long as six hours after the violence started.
Two leading presidential candidates have suspended campaigning in protest at the way authorities handled it.
Abdul Moneim Aboul Fotouh, an
independent Islamist, and Mohammed Mursi, head of the Muslim
Brotherhood's Freedom and Justice Party (FJP), criticised the
authorities' response.
In addition, the FJP and the
Salafist Nour party, which together control 70% of the seats in
parliament, decided to boycott a meeting with the ruling Supreme Council
of Armed Forces (Scaf).
