The United Nations stopped distributing aid to the Gaza Strip on Thursday after running out of fuel as the Israeli terminal that supplies the besieged Palestinian territory remained shut.
"We have just stopped the distribution of all food aid to 650,000 Palestinian refugees in the Gaza Strip because of the lack of fuel in our storage in Gaza," said Adnan Abu Hasna, a spokesman for the UN Relief and Works Agency (UNRWA) office in Gaza.
"We also stopped transporting students and officials in the Gaza Strip," he told AFP. "Not a litre of fuel came from Israel," he added.
Israel, which maintains a punishing blockade on the impoverished territory, claimed the Islamist Hamas movement was preventing distribution of one million litres of fuel (260,000 gallons) delivered about a week ago to the Nahal Oz terminal on the Gaza border.
UNRWA said the stored fuel was not destined for UN agencies in Gaza, which buy their own supplies but also have to import them through Nahal Oz.
Israel suggested that the United Nations complain to Hamas, which runs Gaza.
"They should take it up with Hamas and demand they get fuel from the million litres stored on the Palestinian side of the border," foreign ministry spokesman Arye Mekel said.
"We did try today to transfer fuel directly to UNRWA but a farmers' demonstration supported by Hamas prevented us from doing so," he told AFP.
"Hamas has prevented the use of this fuel stocked for humanitarian purposes such as ambulances, generators, hospitals and water pumps," Mekel added. "Hamas is creating an artificial and dishonest crisis."
An Israeli military spokesman said it was impossible to deliver any more fuel until existing supplies are picked up.
"We have no room -- the tanks are full," he said.
John Ging, who heads the UNRWA offices in Gaza, said Israel had promised to supply 100,000 litres of diesel and 20,000 litres of petrol to the United Nations.
"It is unacceptable that the UN should find itself having to consider suspending its humanitarian operations simply for a lack of fuel for its vehicles," EU Humanitarian Aid Commissioner Louis Michel said in a statement.
"It is also unacceptable that public services such as garbage collection, sewage treatment or hospitals are at the brink of collapse for the same reason," Michel added.
Israel stopped supplying petrol and diesel and cut fuel supplies for Gaza's power plant by half after Palestinian militants attacked Nahal Oz two weeks ago, killing two Israeli civilian employees.
It resumed shipments of fuel for the power plant several days later, but again halted deliveries after another attack killed three Israeli soldiers near the crossing.
Israel has sealed the Gaza Strip off from all but vital humanitarian aid since Hamas, a movement pledged to its destruction, seized control of the territory last June.
Robert Serry, the UN's special envoy to the Middle East peace process, on Wednesday urged Palestinian militants to stop attacking border crossings and called on Israel to lift its blockade.
Humanitarian agencies say Gaza, one of the world's most densely populated areas where 1.5 million people living on a narrow sliver of land, is on the brink of disaster.
Israel says the sanctions it applies are necessary to pressure Hamas to end near-daily rocket attacks on Israeli communities and military positions near the fenced-off Gaza border.
The situation in Gaza was highlighted on Wednesday at a UN Security Council session in New York that saw Western ambassadors walk out in protest after the Libyan delegate compared conditions in the strip to those in Nazi death camps.