The officials say the attack Tuesday also wounded six other soldiers. The officials spoke on condition of anonymity because they were not authorized to speak to the media, the Associated Press reports.
There was no immediate claim of responsibility for the attack, which bore the hallmarks of the Daesh (ISIL) group, which is fighting army and security forces in northern Sinai.
Militants have been battling security forces in that area for years, but their attacks have grown much deadlier and more frequent since the ouster in July 2013 of the Mohammed Mursi, Egypt's first freely elected president, following mass protests against his divisive, one-year rule.