Unknown assailants torched two police vehicles early on Friday morning in the district of Haram in the governorate of Giza.
Three fire engines were called to extinguish the fire, which injured three police conscripts.
According to security forces, the unknown assailants fled the scene after torching the vehicles.
Several police cars and checkpoints have been torched in the past months.
Egypt witnessed an escalation of violence against the security forces following the ousting of president Mohamed Morsi in July 2013, leaving dozens of security personnel dead.