A rocket-propelled grenade has been fired at a state-owned satellite station in Cairo, wounding two people, security officials have said.
There was no immediate claim of responsibility for the attack.
Earlier, gunmen killed five Egyptian soldiers near the Suez canal as further violence swept the country.
Egypt has experienced widespread unrest since Mohamed Mursi was removed from office by the army in July.
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As the silence came to an end the crowd began to applaud and people shouted "I am not afraid!" in defiance of the attacks.