Egyptian military raids on Saturday killed 40 "terrorist operatives" following a deadly attack targeting tourists as they traveled close to the Giza pyramids outside Cairo, officials said.
The bomb was planted on the roadside of Al Haram Mariotia Street in Giza, southwest of Cairo, the authorities said.
No immediate claim of responsibility was reported.
The bomb was hidden beside a wall and went off as the tourists' bus was passing in the city of Giza.
No group has yet said it was behind the blast, which killed three Vietnamese tourists and an Egyptian tour guide, but Islamist militants have targeted tourists in Egypt in the past.
Madbouly said that terrorism is a real threat to the entire world; however it's important to control it by taking all needed security measures.
Three of the tourists were killed along with the tour guide, an Egyptian citizen, Attorney General Nabil Ahmed Sadeq said in a statement.More news: As of late afternoon, no CenturyLink ETA for restored Internet service
More news: After Trump visit, Iraqi lawmakers demand US withdrawal
More news: Debutant Agarwal shines as India dictate play on Boxing Day
Later, a statement issued by the United States condemning the attack.
But Friday's attack is the first to target foreign tourists in nearly two years.
"Information was received by the national security that a group of terrorists were planning to carry out a series of aggressive attacks targeting state institutions, particularly economic ones, as well as tourism, armed forces, police and Christian places of worship".
Tourism is a mainstay of Egypt's economy.
In July 2017, two German tourists were fatally stabbed by a suspected jihadist at the Egyptian Red Sea beach resort of Hurghada.
Egypt has battled Islamic extremists for years in the Sinai Peninsula in an insurgency that has spilled over to the mainland at times, hitting minority Christians or tourists.
In October 2015, a bomb claimed by a local affiliate of Daesh killed 224 people on board a passenger jet carrying Russian tourists over the Sinai peninsula.