An international team of scientists and architects have revealed a mysterious thermal anomaly in the Great Pyramid of Khufu, the largest and oldest of the three pyramids in the Giza pyramid complex in Egypt, the country’s antiquities officials say.

In a statement released on Monday, the Egyptian Ministry of Antiquities announced that “among the various identified thermal anomalies, the team has observed a particularly impressive one located on the eastern side of the Khufu Pyramid at ground level,” adding that in this part of the pyramid, an area of few blocks were hotter - up to six degrees Celsius - than its neighboring blocks.

According to the statement, many hypotheses and possibilities could be drawn up, including the presence of voids behind the surface, internal air currents or different materials used in building pyramids.

A thermal anomaly on these blocks, belonging to the Great Pyramid of Khufu in Egypt, has raised new questions about the ancient pyramids. (HIP)

“Khufu will offer us today one of its secrets,” Mamdouh al-Damati, the Egyptian Antiquities Minister, told reporters.

The project, called the Operation Scan Pyramids, was initiated on October 25 by the Faculty of Engineering of Cairo University and the French Institute of Heritage, Innovation and Preservation (HIP), under the authority of Egyptian Ministry of Antiquities in order to identify the presence of unknown internal structures and cavities.

A six degrees centigrade gap in temperature was detected between these stones and their neighboring blocks on the eastern side of the Khufu Pyramid at ground level. (HIP)

The project, which is expected to last at least until the end of 2016, uses a mix of technologies, including infrared thermography, photogrammetry, and 3D reconstruction to scan the two Gizan pyramids of Khufu and Khafre, situated on the outskirts of the capital Cairo. The Bent and Red pyramids at Dahshur, located on the west bank of the Nile almost 40 kilometers (25 miles) south of Cairo, were also included in the project.

Other institutions, such as Canada's Université Laval of Quebec and Japan's Nagoya University, also contributed to the project.

The findings came as the results of the first phase of the project.

Antiquities Minister Mamdouh al-Damati (L) standing in front of the hot stones of the Great Pyramid of Khufu in Giza on the outskirts of Cairo on November 9, 2015 (Reuters)

“This area should be the subject of further investigation during the subsequent phases of the project,” the statement further added.

Mamdouh al-Damati (L), Jean Claude Barre (C) of the Heritage Innovation Preservation institute, and Hany Helal of the Faculty of Engineering of Cairo University, attend a press conference in front of the Great Pyramid of Khufu in Giza on the outskirts of Cairo on November 9, 2015. (AFP)

Khufu’s pyramid was erected some 4,500 years ago during a 10 to 20 year period by the order of Pharaoh Khufu of the Fourth Dynasty of ancient Egypt. It is the oldest of the Seven Wonders of the Ancient World and the only one that remains largely intact.

The pyramids in Egypt were mostly built as tombs for the country’s pharaohs and their consorts.