A young man was killed and three others injured when a bomb exploded on Egypt's north coast, close to its second city Alexandria, Al-Ahram's Arabic news website reported.
The bomb targeted a security convoy on the Alexandria-Marsa Matrouh highway, 21 kilometres from the former city.
Preliminary investigations showed that the explosive device was triggered via a mobile phone. The injured were transported to hospital.
An insurgency against Egyptian security forces, mainly in Sinai, though sometimes in other governorates, spiked after the ouster of Islamist president Mohamed Morsi in 2013. Civilians have at times been caught up in the violence.