Tens of thousands of people in Gaza are without electricity after Israel closed its borders in response to Palestinian rocket attacks. Officials at the Gaza power plant say it cannot operate because fuel shipments have not arrived and there are no reserves.
The plant supplies about a third of the electricity to Gaza, with the remainder coming from Israel and Egypt.
Israel has tightened sanctions on Gaza since June, when the Islamic militant group Hamas seized control of the territory, routing the Fatah forces of western-backed Palestinian President Mahmoud Abbas.
The United Nations condemned the Israeli measures, saying they are leading to a humanitarian crisis among Gaza's 1.5 million residents. John Ging is a senior U.N. official in Gaza.
"Everything is in short supply, all reserves have run out, and we are living here day to day," Ging said.
Israel closed its border crossings with Gaza on Friday, after Hamas fired more than 100 rockets at the Jewish state in three days. Hamas stepped up attacks in response to Israeli raids in Gaza that are taking a heavy toll on Palestinian fighters.
Israeli analyst Jonathan Fighel says the sanctions on Gaza are justified.
"The fact that a sovereign country is being attacked by missiles, this is totally inconceivable and totally unacceptable and the leadership of the Palestinian terror organizations have to pay a price," Fighel said.
Israel says it will ease the closure when the rocket attacks stop. But Hamas is defiant. It issued a statement saying that Israeli sanctions would not weaken "the determination and steadfastness" of the Palestinian people."