One man was wounded in a firefight between the security detail of Egyptian Prime Minister Hisham Qandil and alleged thugs Sunday but the security service said the incident was not political in nature.
Bodyguards opened fire at a car carrying five people that had cut into the official convoy as it crossed the capital's October 6 bridge across the Nile.
The fire was returned from the car before the driver and the passengers were arrested.
A security official said the suspects claimed they had been unaware of Qandil's presence in the motorcade and had not shot at his car.
The injured man was an unsuspecting motorist.
Egyptian media reported in February that protesters threw stones and bottles at the prime minister's motorcade as he tried to enter Cairo's Tahrir Square after overnight clashes nearby and at the presidential palace.
His office said in a statement later, without elaborating, that he had been "confronted by youths and troublemakers".