Egypt's Antiquities Ministry says a scanning project in the Giza pyramids has identified thermal anomalies, including one in the largest pyramid, built by Cheops, known locally as Khufu.

The ministry says in a statement Monday that the first phase of the scanning has shown "a particularly impressive one (anomaly) located on the Eastern side of the Khufu pyramid."

The thermal scanning was carried out during sunrise, as the sun heats the structures from the outside, and then during sunset as the pyramids are cooling down. The speed of the heating and cooling phases was used to uncover "hypotheses" such as empty areas in the pyramids, internal air currents, or different building materials used.

The structures are over 4,500 years old.