Security officials say Egyptian soldiers have been deployed to guard a northern Sinai pipeline that carries natural gas to Israel.
On 5 February, assailants bombed a gas terminal in the area, disrupting the flow of gas to Israel and Jordan.
The security officials said Thursday that soldiers have been taking up positions along the line since Tuesday.
The northern Sinai is home to Bedouin tribes who resist government control. Officials say tribesmen have joined forces with Islamic militants, some of whom escaped from prisons during the uprising that led to Egyptian President Hosni Mubarak's ouster last week.
The groups have attacked police stations in the Sinai.
The officials spoke on condition of anonymity under briefing regulations.