Four conscripts and a police officer were injured late Friday when unknown assailants shot at a police patrol on the ring road connecting Egypt's capital city Cairo, according to an interior ministry statement.

Greater Cairo's ring road connects the governorates of Cairo, Giza and Qalyubia.

According to the statement, the shooting took place on the part of the road that falls under the jurisdiction of Qalyubia.

A security source told Aswat Masryia that the shooting came from a building top located in the agricultural area surrounding the road.

The policemen shot were on their way back from the neighbourhood of Shubra El-Kheima where they had been stationed.  

Security forces surrounded the area of the shooting in search of the assailants, the interior ministry stated. 

Egypt's police have been facing a wave of militant attacks since the ouster of Islamist president Mohamed Morsi in 2013.

In Egypt's Sinai, an Islamic militant insurgency has battled security forces for over a decade and stepped up its attacks over the past two years, leaving hundreds killed.