Security officials told Reuters news agency that those people wounded included tourists.

And disturbing pictures from the blast scene on social media showed at least one person covered in a pool of own blood.

The attack comes as Egypt’s vital tourism industry shows incredible signs of recuperation after years in the doldrums because of the political turmoil and violence that followed a 2011 uprising that toppled former leader Hosni Mubarak.

And in less than six months, this is the second to target foreign tourists near the famed pyramids.

Three Vietnamese tourists and an Egyptian guide In December were killed and more than 10 others were injured when a roadside bomb hit a tour bus less than four kilometres from the Giza landmarks.

A political analyst, Timothy Kaldas, a non-resident fellow at US-based, The Tahrir Institute for Middle East Policy said it was “too early to know” who was responsible for Sunday’s blast.

Kaldas told Al Jazeera, “The last time we had an attack on a tourist bus that had been leaving the pyramids in December, no one ended up claiming responsibility.

“Historically these sorts of attacks have been followed by announcements of raids on different militant groups outposts.”