A security officer and two recruits were injured when an explosive charge went off in southern Sheikh Zweid city, in Sinai on Tuesday.
According to security sources, unidentified people planted the bomb along the road leading to Al-Toma village.
The bomb was detonated by remote control when a security patrol was passing by.
The patrol was taking part in combing and crack down operations in the area.
The three were carried to hospital for medical treatment. Their health condition, however, is reassuring.