The officials said the bomb struck an armored vehicle carrying soldiers to Sheikh Zuwaid near the city of el-Arish city Saturday. The four soldiers, they said, are in a critical condition and the death toll could rise, AP reported.
The officials spoke on condition of anonymity because they were not authorized to speak to the press.
Egypt has battled Takfiri militants in Sinai for years, but the insurgency has grown deadlier and spread into the mainland since the 2013 ouster of president Mohamed Morsi.
A local affiliate of Daesh (ISIL or ISIS) is the most active faction and it has claimed responsibility to the near-daily attacks there.