Egypt opened three tombs in the ancient city of Luxor to the public for the first time on Thursday, hoping to spur interest in tourism despite the shadow of last weekend's airline crash in the Sinai Peninsula.

"It is very sad what happened, but we have to wait for the result of the investigation," Antiquities Minister Mamdouh Eldamaty said, before descending into one of the newly opened tombs. "It was not a terror act, it was an accident."

The most significant tomb opened Thursday was that of Huy, Viceroy of Kush under the famed King Tutankhamun. Inside the tomb, wall paintings depict a great festival with southerners from Nubia paying tribute, confirming Egypt's domination.

"The tomb also shows Huy receiving the seal of his office, and other unparalleled details regarding the administration of Egypt's most important foreign holdings," said John Darnell of Yale University. "In many ways the tomb of Huy gives us one of the most detailed and colorful glimpses into the interactions of Egyptians and Nubians during the high noon of imperial Egypt."

Eldamaty said the newly opened tombs, in the Qurnat Marey area of Luxor, are among the most important ones made for nobles of the New Kingdom period, which ended over 3,000 years ago. The opening, planned before the airline disaster, is part of government plans to highlight new archaeological sites to encourage tourism.

Most of the tombs in Luxor are secured against unauthorized entry, but the ministry keeps several open at any given time, rotating access regularly to give them a rest from humidity and visitors.

The two other tombs opened Thursday are known as Tomb TT 277 of Amunemonet, a priest in the funerary temple of Amenhotep III, and Tomb TT 278 of Amunemhab, who was the keeper of the cattle belonging to the temple of the god Amun Re.

The cause of Saturday's crash of a Metrojet flight packed with Russian vacationers returning home from the Red Sea resort of Sharm el-Sheikh is under investigation, but the Islamic State extremist group has claimed responsibility and British Prime Minister David Cameron said it was "more likely than not" that a bomb brought down the flight. All 224 on board were killed.

Cameron has grounded all British flights to and from Sinai, stranding thousands of tourists, citing "intelligence and information." Germany's Lufthansa Group said later Thursday it was also suspending all flights to and from Sharm el-Sheikh.

Officials from Russia and Egypt are dismissing the bomb theory as premature speculation. Many Egyptians in tourism-dependent areas are repeating the line with a sometimes desperate hopefulness.

Tourism, a key foreign currency earner for Egypt's economy, is making a gradual recovery after years of political upheaval, but the future would be grim if it's proven that an Islamic State bomb indeed brought down the Russian passenger plane. The army is already fighting in a northern corner of Sinai Islamic militants who in recent months claimed allegiance to the Islamic State group, but such a revelation would undermine its claims that it has the insurgency under control and that Egypt is safe for tourists.