The state-run MENA news agency said attackers set off explosives near the pipeline carrying natural gas upstream to Israel and Jordan. The same pipeline, the official Petra news agency in Jordan said, was bombed Friday. It wasn't transmitting natural gas, however, because of earlier attacks.
The attack Monday was the ninth such attack since demonstrators ousted Egyptian President Hosni Mubarak from power in early February. It coincided with the country's first post-revolution elections Monday.
Israel gets about one-quarter of its electricity needs from natural gas supplied through Egypt, though Jordan imports most of the energy it needs.
In mid-November, the official Egypt State Information Service reported an earlier explosion had damaged part of the pipeline. Authorities arrested a suspected militant last week they believe was behind earlier attacks.
Al-Qaida leader Ayman al-Zawahiri, an Egyptian, praised the "heroes" who attacked the same pipeline earlier this summer.