An explosive device blew up in Rafah as a bus belonging to central security forces was passing by on Friday morning, security sources said.
Unknown assailants planted the device on the side of the road in Sadot area. The device detonated when the bus passed right by it, causing minor external damage to the bus.
Extremists intensified their attacks on police and army forces in Sinai since former President Mohamed Mursi was removed from power last July.
More than 100 security personnel were killed in Sinai alone since the former president's removal.
In a separate incident, security forces defused another explosive device before it detonated after residents of Abu Refai area reported it to the police, sources said.
Unidentified people planted the device on a route taken by army tanks that sweep the area in pursuit of armed elements, they added.