UN aid agencies say that Gaza is on the brink of a public health disaster and civilians were disproportionately paying the price in Israel's military offensive.
Some 50 Palestinians have been killed since Israel sent its forces into the Gaza Strip 11 days ago to try to free a captive soldier and prevent militants from firing rockets at Israeli cities. Among the seven Palestinians killed on Saturday was a six-year-old girl.
"Civilians are disproportionately paying the price of this conflict," UN agencies said in a joint statement sharply critical of Israeli military operations.
The agencies said they were "alarmed by developments on the ground, which have seen innocent civilians, including children, killed, brought increased misery to hundreds of thousands of people and which will wreak far-reaching harm on Palestinian society."
The agencies said the Karni and Nahal Oz crossings into Gaza from Israel "must remain open 24 hours a day if humanitarian need is to be adequately met."
The United Nations also called on Israel to repair the damage its bombs caused to Gaza's main power plant.
Since the June 28 bombing, the entire Gaza strip has been without electricity for between 12 and 18 hours each day, the United Nations Relief and Works Agency said.
The agency said generators that power Gaza's water wells and sewage pumping plants were running low of fuel.
The World Health Organisation said the public health system was also facing an unprecedented crisis.
While Gaza's hospitals and 50 per cent of its primary care clinics have generators, the stock of fuel to power them will last for a maximum of two weeks, WHO said.
The agency said there has been a 160 per cent increase in diarrhoea cases in the last week, compared with the same period last year.
The World Food Programme said wheat flour mills, food factories and bakeries were being forced to reduce production due to power shortages.
Supplies of sugar, dairy products and milk are running low due to limited commercial supplies from Israel.
As a result, food prices have increased by 10 per cent in the past three weeks, the World Food Programme said.