Fifteen people were killed on Friday and 87 injured during clashes between supporters of the Muslim Brotherhood and opponents across Egypt, the health ministry said on Saturday.
School pupil Abdullah Nawara died in Damietta, which saw supporters of ousted Islamist president Mohamed Morsi squarring off with police and local residents in the north Nile Delta's governorate.
Pro-Morsi protesters shouted slogans against the police and army until security forces arrived and dispersed them with teargas. Eleven others were reportedly injured in the clashes.
Twelve others were arrested during the violence, Al-Ahram added.
Clashes also erupted in Alexandria during a funeral for a student killed in previous clashes in the city on Thursday, leading to the death of another protester.
Supporters and opponents of the Brotherhood threw bricks and stones in the Al-Dekheila district, in the western part of the city, with protesters blocking a road before police intervened to separate both sides.
Fierce clashes also broke out in Giza between Morsi supporters and Egyptian security forces.
Hundreds of Islamists gathered in the Imbaba district, west of Cairo, with some burning tyres and hurling lit fireworks at security forces, who responded by firing tear gas, news agency MENA reported.
Sources told Ahram Online that one died in the Imbaba clashes. At least 111 rioters have been arrested in several governorates, the interior ministry said.
In Beheira governorate in Egypt's Nile Delta, two were killed in clashes between the Brotherhood and residents of Housh Eissa city, reported Al-Ahram's Arabic news website.
In Upper Egypt's Beni Suef governorate, the health ministry said that four people were killed during clashes between police and Brotherhood supporters.
Security forces said they arrested 20, two of whom are leading Brotherhood members -- Mahmoud Fouad and Mohamed Sayyed Abdo. Protests had erupted following Friday prayers in the cities of Beni Suef and Al-Wasti which soon after developed into confrontations.
In Upper Egypt's Minya governorate, Emad Sadek, 54, a shop owner, died from gunshot wounds sustained as he was passing close to the clashes. One more was injured, according to a health ministry official speaking to Al-Ahram's Arabic news website.
Clashes in Upper Egypt's Fayoum governorate also led to the death of 3, according to the latest health ministry figures.
At least six others were killed and more than 80 injured in Cairo in three separate bomb attacks targeting police buildings and personnel.
Friday's bomb attacks have heightened tensions in Egypt a day ahead of planned protests to mark the anniversary of the 2011 uprising.