The health ministry said two persons were killed in Minya in southern Egypt, a third in Cairo and one in Giza. At least 15 people were injured in clashes as police dispersed anti-government protests.
Police used teargas and birdshot to scatter supporters of ousted Islamist president Mohamed Morsi and other anti-government activists.
Earlier today, two explosions hit Cairo as thousands joined demonstrations across the country to mark the anniversary of the uprising that toppled president Hosni Mubarak.
An al-Qaeda-inspired militant group Ansar Beit al-Maqdis (Champions of Jerusalem) claimed responsibility for yesterday's attacks.
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Over 150 people, mostly pro-Morsi activists, were arrested all over Egypt, ahramonline reported.
Thousands of supporters of the interim military-backed government also gathered to celebrate the anniversary of the revolution in Tahrir and other squares around the country.
Sources said anti-Muslim Brotherhood crowds gathered in Tahrir square, with more arriving throughout the day, chanting "the people demand the execution of the Brotherhood" and "the people demand the affirmation of the regime", Al Jazeera reported.
Ahead of commemorations, security forces had blocked areas of the capital, including Tahrir Square, the epicentre of the popular revolt that toppled Mubarak in 2011.
Mubarak was forced to step down on February 11, 2011 after 18 days of demonstrations in which an estimated 850 people were killed.