Forty-nine people were killed in clashes during rallies in Egypt, as the country marked the third anniversary of the overthrow of former president Hosni Mubarak.
In rival demonstrations, anti-government marches took place in Cairo and elsewhere while thousands gathered in the capital's Tahrir Square in support of army-led authorities.
Security forces lobbed tear gas and fired in the air to try to prevent demonstrators opposed to the government from reaching the central Cairo square - the symbolic heart of the 2011 uprising.
Not far from Tahrir Square, police fired tear gas canisters in a clampdown on anti-government protesters lasting for about two hours.
A state run website quoted a health ministry official as saying the death toll has risen to 49.
Two people were killed in the southern town of Miny and a woman died in Egypt's second city of Alexandria in clashes between security forces and supporters of Islamist ex-president Mohammed Morsi.
Army chief General Abdel Fatah al-Sisi toppled Mr Morsi of the Muslim Brotherhood in July after mass protests against what critics called his mismanagement and increasingly arbitrary rule, triggering a confrontation with the veteran Islamist movement that has hit investment and tourism hard.
The general, who served as head of military intelligence under Mubarak, is expected to announce his candidacy for the presidency soon and likely to win by a landslide in elections, expected within six months, Reuters reports.
The army congratulated Egyptians on the anniversary of the 2011 uprising and said it would help people build on the gains of what it calls the June 30 Revolution, a reference to the street unrest that prompted the army to oust Mr Morsi.