The main power plant in the Gaza Strip is not operating because of a shortage of fuel.
One turbine at the plant was shut down on Sunday, causing blackouts.
The remaining two turbines were shut down late on Monday.
Shipments of industrial fuel from Israel were halted last week after border clashes and rocket fire.
The Gaza City plant provides about a quarter of Gaza's electricity and more than half the electricity used by the city itself.
Most of the rest of the supply to the territory of 1.5 million people comes directly via power lines from Israel.