Activists accused Egyptian police of using excessive force on Saturday during violent protests outside the country's capital.
Protesters in Mansoura and Port Said have been calling for civil disobedience campaigns and work stoppages to bring down the president.
The Interior Ministry said one protester died and dozens were wounded in Mansoura, where about 400 people protested outside the local council office.
Activists said that 14-year-old protester Hossam Eldin Abdullah Abdelazim was killed when an armoured police vehicle crushed him to death during the clashes.
By nightfall, demonstrators were still clashing with police, who fired tear gas and birdshot.
The ministry said 12 officers were hurt, nine by birdshot. Police arrested 28 people.
Elsewhere in Egypt, a police car in Port Said hit five protesters on a main road and drove off.
The protesters were blocking traffic during an anti-government march when the car rammed the crowd.