(All times are local in Egypt, GMT+2)
4:58pm Protesters in the north Sinai town of El-Arish exchanged gunfire with police and hurled Molotov cocktails at a police station, witnesses said. About 1,000 protesters broke off from a larger group and headed towards a police station, lobbing firebombs and burning police cars, witnesses said.
4:53pm Military helicopters arrive at Cairo's Presidential Palace ahead of expected statement - more details soon.
4:39pm The Egyptian presidency is to make an "urgent and important" statement shortly, state television says