Three Vietnamese holidaymakers and an Egyptian tour guide were killed Friday when a roadside bomb blast hit their bus as it travelled close to the Giza pyramids outside Cairo, officials said.
A statement by the public prosecutor's office said 11 other tourists from Vietnam and an Egyptian bus driver were wounded when the homemade device exploded.
The improvised explosive device was placed near a wall along the Mariyutiya Street in Al-Haram district near the Giza Pyramids, it said.
The bus was carrying a total of 16 people including 14 Vietnamese tourists, an Egyptian driver and a tour guide, according to the statement.
Armed security personnel quickly deployed to the site and cordoned off the area for inspection.
The white tourist bus could be seen with its windows shattered and surrounded by soot-covered debris.
Prime Minister Mostafa Madbouli visited the injured tourists in hospital, where he announced that the tour guide had died from his wounds.
Madbouli urged against "amplifying" the incident as he insisted that "no country in the world can guarantee that its 100 percent safe".
"It's possible at times that an individual incident takes place here or there," he told journalists.
"We have to know that it's possible that it would be repeated in the future."
There was no immediate claim of responsibility for the blast. Later, a statement issued by the United States condemning the attack.
"We stand with all Egyptians in the fight against terrorism and support the Egyptian government in bringing the perpetrators of this attack to justice," State Department spokesman Robert Palladino said.