Unidentified men set three buses ablaze in Zagazig, Faqous and Abu-Kbeir cities of Sharkia province, but no causalities were reported, police said.
A bus was torched in a garage in Zagazig city while two buses were set ablaze in other parts of the province, a security source said.
Officials said the buses were completely charred and cannot be used.
Initial investigations showed that unidentified men hurled petrol bombs at the buses and fled the scenes.
The prosecution has launched a probe into the incidents