The only power plant in the Gaza Strip has been closed by energy authorities because they say Israel will not allow the urgent delivery of spare parts.
Officials said the plant had been damaged by frequent shutdowns because of fuel shortages and needed repairs.
Officials say the power plant shutdown was the cumulative result of months of being unable to receive replacement parts.
"Despite deliveries of fuel on Monday, the power plant stopped functioning because of breakdowns in the production units," the assistant director of the authority, Kanaan Obeid, told AFP.
Israel "refuses to allow in the necessary parts and the plant cannot restart without them," he added.
The United Nations relief agency in Gaza (Unrwa) has warned of a worsening humanitarian crisis unless the crossings are opened.
The closure means that about 500,000 people - one-third of Gaza's population - are without electricity.