People reported hearing the blast throughout Greater Cairo, including in Maadi, 6 October City, and Sheikh Zayed.

“What happened was the result of construction work on the electric railway in eastern Cairo, which resulted in the expelling of energy in the form of a strong shockwave,” said the NRIAG.

Egypt is currently constructing a high-speed electric railway network with a length of 1,800 kilometres that links the country's eastern and northern coasts. The railway will serve up to 30 million people annually, cutting their travel time from an average of two to four hours.

When finished, the train will be the world's sixth longest high-speed network, according to Michael Peter, CEO of Germany's Siemens, which was awarded the venture.

A consortium made up of Siemens Mobility, Orascom Construction and the Arab Contractors has signed a contract with Egypt’s National Authority for Tunnels to deliver the country’s first high-speed, electrified main and freight rail line.

The $23 billion electrical system’s first phase is set to be completed in 2023.