Fire broke out after a leak from the Shuqair-Mostorod pipeline next to a busy highway in Cairo on Tuesday, injuring 17 people.
A spark caused by passing cars ignited crude oil that was leaking from the pipe. There was no immediate word from authorities on why the pipeline, located some 1.5-meter (5-ft) deep in the ground, had leaked.
A witness at the scene said about two dozen cars were torched, apparently abandoned by motorists. A video posted online showed two residents pulling an injured person away from the highway while thick plumes of smoked billowed skyward.
Petroleum Ministry spokesman Hamdy Abd El Aziz told local TV officials had cordoned off the pipeline and road when the leak had been discovered but motorists had kept driving by which probably sparked the fire.
He did not say when pumping would resume or how much crude had been flowing when the fire broke out. He also refused to say how the underground pipeline could have been damaged, referring to a committee investigating the incident.
The crude pipeline runs from the Red Sea oil port of Shuqair to the called Egyptian Refining Co (ERC) complex of Mostorod in Greater Cairo.