A power cut at the Egyptian state TV building took most state-run channels off the air for about 50 minutes on Saturday evening, state media reported.

Local media outlets said Saturday evening's interruption was the first time the mouthpiece of the state has gone dark since its inception in 1960.

"It's a matter of national security. It's extremely dangerous to have this situation," said veteran state channel news anchor Amr Shennawi.

Egypt's Minister of Electricity Mohammed Shaker, who was en route to Saudi Arabia at the time, immediately returned to Cairo to follow up on the matter, state media reported.

Prime Minister Ibrahim Mahlab ordered an investigation into the causes of the power cut. State media reported backup generators at the state TV building, which typically operate automatically in case of a power outage, malfunctioned.

Egypt, the Arab world's most populous country, faces a chronic power shortage causing rolling blackouts, particularly in summer, that affect tens of millions of people.

Shennawi said power cuts happen "all the time" at state television but typically the backup power system works well.

Shortly after the state channels came back on the air, Essam Amir, head of the Egyptian Television and Radio Union, brought cameras into the building's main power hub and said repeatedly that there were no signs of sabotage.

Government officials have said the cause of the nationwide power crunch is poor maintenance and a lack of funding. Some officials have also blamed the Muslim Brotherhood, ousted President Mohammed Morsi's organization, accusing Morsi loyalists of sabotaging the national power infrastructure.