Egyptian officials say a roadside bomb has hit a tourist bus near the Giza Pyramids.
They say the blast wounded at least 16 people, including tourists. One security source said they included South African nationals.
There were no reports of deaths. A witness, Mohamed el-Mandouh, told Reuters he heard a "very loud explosion" while sitting in traffic near the site of the blast.
Pictures posted on social media showed a bus with some of its windows blown out or shattered, and debris in the road next to a low wall with a hole in it.
Egypt has battled Islamic militants for years in the Sinai Peninsula in an insurgency that has occasionally spilled over to the mainland, hitting minority Christians or tourists.
The attack comes as Egypt's vital tourism industry is showing signs of recovery after years in the doldrums because of the political turmoil and violence that followed a 2011 uprising that toppled former leader Hosni Mubarak. It is the second to target foreign tourists near the famed pyramids in less than six months.
In December, three Vietnamese tourists and an Egyptian guide were killed and at least 10 others injured when a roadside bomb hit their tour bus less than 4 kilometres from the Giza pyramids.