Prime Minister Mostafa Madbouly announced the curfew and said it would last for a month initially.

"Shops, shopping centres, restaurants and cafes will all close at 9:00 pm on weekdays," he said, adding that on Thursdays and Fridays at the weekend they will be allowed to stay open until 10:00 pm.

The premier said that before the war, Egypt's monthly energy bill was $560 million. Today, for the same quantity, he said Egypt is paying $1.650 billion.

Madbouly said Cairo must work on the "worst-case scenario" in the face of a war whose outcome is unpredictable.

Tourism Minister Sherif Fathy said the new restrictions "will not affect tourists" or flagship destinations, a statement from his office said.

At the beginning of March, Cairo was forced to raise fuel prices by more than 30 percent, after strikes on regional oil infrastructure and threats against the Strait of Hormuz, the crucial shipping route now virtually paralysed by the war.

Around a fifth of global crude oil and liquefied natural gas passes through the waterway in peacetime.

The rerouting of shipping away from the Suez Canal is also depriving Cairo of a vital source of foreign currency.