It was the first time the military has reported its own casualties since it launched the operation on February 9. The statement did not say where or when the soldiers had died.
The military says it has killed dozens of militants and arrested hundreds of suspected fighters and criminals in the operation, which is taking place ahead of a three-month deadline that President Abdel Fattah El-Sisi set to clear North Sinai of militants.
A group of Sinai-based militants swore allegiance to Daesh in 2014. Attacks by the militants have killed hundreds of soldiers and police and scores of civilians.
Sissi is seeking re-election in March when he will run virtually unopposed.