Gaza's 1.5 million residents are facing an "alarming" humanitarian situation under constant Israeli bombardment, with the main power plant shut down, overcrowded hospitals struggling to cope and very limited food supplies, UN officials said.
UN humanitarian chief John Holmes said the power plant shut down on Tuesday because Israel has blocked fuel delivery.
This has forced hospitals to use generators, which have limited fuel supplies, and left many of the 650,000 people in central and northern Gaza with power cuts of 16 hours a day or more, he said. "On the humanitarian side," Holmes said, "the situation remains alarming".
"Hospitals are obviously still struggling very much to cope with the number of casualties. We have continued to get some medical supplies in and to help them cope, but this remains difficult and fragile," he told reporters at UN headquarters.
Karen Abu Zayd, commissioner of the UN Relief and Works Agency which helps Palestinian refugees, told reporters by video link from Gaza that the agency has not distributed any food for two weeks because of the shortage of supplies and the Israeli bombardment.
"I think that means that 20,000 people a day have been without food that they expect – and probably is the bulk of what they get. It's not just the flour, but it's the protein source, either lentils or tinned meat and the sugar and milk powder and oil," she said. "So people are doing pretty badly. Everyone we know is sharing whatever they have, not just with their families but with their neighbors," Abu Zayd said.
"People are not eating what they used to. That's simply what's happening.
"We haven't seen widespread hunger. We do see for the very first time – I've been here for eight years – people going through the rubbish dumps looking for things, people begging which is quite a new phenomenon as well," she said.
A spokesman for President George W Bush, Gordon Johndroe, told reporters in Texas that American officials are seeing "a good flow" of medical and food supplies into Gaza.
Abu Zayd stressed, however, that UNRWA needs 100 trucks of flour a day to meet the needs of refugees.
But she said Israel has closed down the Karni crossing, the main gateway for cargo into Gaza where it is normally delivered, for security reasons.
She said UNRWA was told by the Israeli humanitarian co-ordinator that all other crossings are not open because "there is intelligence about serious preparations for security operations".
"We wonder if it's serious enough to really keep things completely closed and to keep people on their edge of subsistence," she said.
Holmes said "the major needs, apart from medical supplies, remain… grain and wheat flour and fuel – also cash would be very helpful to enable people to buy supplies." He said the Israelis have been "co-operative in principle about these supplies but we need to see more results."
UNRWA launched an emergency appeal on Tuesday for $34 million (Dh124m) for food, medical supplies and other goods, he said, and "there are good indications that the donors will respond generously".
On the infrasturcture side, Holmes said damage has been limited so far, but two major wells have been hit along with schools and some UN facilities.
Five mosques were also hit by Israeli bombs, Abu Zayd said. Both Holmes and Abu Zayd said the bombing has taken a psychological toll.
Abu Zayd said UN staff members "try to tell their children that the bombing is a wedding and somebody's celebrating".
"The children, of course, know that there's something wrong because they're not going to school," she said. "They were supposed to take their exams this week," said Abu Zayed.
"Everyone is just traumatised by what's happening each day, and also their worries about the future, because they don't know what's going to happen next... they're just expecting the worst," Abu Zayd said.