CAIRO (AP) — Egypt’s antiquities authorities on Thursday unveiled a newly discovered, sealed-off chamber inside one of the Great Pyramids at Giza, just outside of Cairo, that dates back some 4,500 years ago.

The corridor — on the northern side of the Pyramid of Khufu — was discovered using modern scanning technology. It measures 9 meters (nearly 30 feet) in length and is 2 meters (over 6 feet) wide, perched above the main entrance of the pyramid.

Archaeologists do not know what the function was of the chamber, which is not accessible from the outside. In 2017, scientists announced the discovery of another sealed-off corridor, a 30-meter chamber — or about 98 feet — also inside the Pyramid of Khufu.

Egyptian archaeologist Zahi Hawass and the country’s Minister for Tourism Ahmed Eissa, announced the discovery Thursday at an unveiling ceremony outside the pyramid. The Scan Pyramids project, an international program that uses scans to look at unexplored sections of the ancient structure, was credited for the find.

Scientists from the project — which began in 2015 — attended the unveiling.

According to Christian Grosse, Professor of Non-destructive Testing at the Technical University of Munich and a leading member of the project, various scanning techniques were deployed to locate the chamber, including ultrasound measurements and ground penetrating radars. He hopes these techniques will lead to further findings within the pyramid.

‘’There are two large limestones at the end chamber, and now the question is what’s behind these stones and below the chamber,’’ Grosse said.

The Pyramid of Khufu — named after its builder, a Fourth Dynasty pharaoh who reigned from 2509 to 2483 B.C. — is one of three pyramids that make up the Great Pyramids at Giza complex. The Egyptian pyramids are the only one of the ancient Seven Wonders of the World that have survived to this day.

Experts are divided over how the pyramids were constructed, so even relatively minor discoveries generate great interest. Authorities often publicly tout discoveries to attract more tourists, a major source of foreign currency for this cash-strapped Middle eastern country.

Egypt’s tourism sector suffered a long downturn after the political turmoil and violence that followed the 2011 uprising that ousted the country’s longtime autocratic President Hosni Mubarak, and further setbacks following the outbreak of the coronavirus pandemic.