Five Egyptian police officers were killed by unidentified gunmen in the northern Sinai town of al-Arish on Friday, a security official told AFP.
He said that the policemen were guarding a government building, adding that the gunmen were on motorcycles and immediately fled the scene of the crime.
Ealier on Friday, three protesters backing Islamist President Mohammed Mursi were killed by the army, said reports. However, the military later denied that it used live ammunition against the demonstrators.
Thousands of people gathered at the Rabaa al-Adawiya mosque to defend Mursi, who was overthrown on Wednesday by the military.
Meanwhile, pro-Mursi protesters headed towards the state TV building in Cairo and blocked the road in front of the station, Al Arabiya's correspondent reported.