Egypt's military has detained five people suspected of involvement in clashes between gunmen and police in northern Sinai, official media reported Saturday, DPA reported.
Four people were killed and 19 injured on Friday when dozens of gunmen tried to storm the police station in al-Arish in northern Sinai.
The armed forces arrested four men suspected of involvement in attacking the police station, while another man was arrested driving nearby with two machine guns in his car.
Around 150 people, reported to be Islamists and carrying signs reading "There is no God but God," tried to storm the police station.
They destroyed a statue of former president Anwar Sadat, who was killed by Islamist militants in 1981.
Witnesses said that the attackers were not residents of the city.
The violence came hours after a massive demonstration in Cairo's Tahrir Square that was dominated by Islamists holding up placards demanding the implementation of Sharia law.