Egypt’s state-run broadcaster Nile News TV said the bus was carrying 25 South African nationals, among them seven were injured along with 10 Egyptian civilians.
Other reports said at least 17 people were wounded in the blast, but there are no reports of deaths.
No group has claimed responsibility for the attack.
However, such bombings are redolent of tactics the so-called Islamic State has employed in the past, often targeting crowded areas with civilians and tourists.
In December 2018, a bomb targeting a small tourist bus near Egypt’s famed pyramids, killed three Vietnamese tourists, along with their Egyptian tour guide.
Another eleven of the 14 tourists on the bus were injured.
Two years prior, in December 2016, the Islamic State claimed credit for a terrorist assault on the Coptic Orthodox cathedral in Cairo which killed 29 people.