Jan. 4, 2009 -- The long-suffering residents of the Gaza Strip, who before Saturday's Israeli invasion were already facing severe shortages of food, shelter, medicine and other basic daily necessities, are now caught in an even more grave humanitarian crisis, the United Nations said over the weekend.
The Israeli offensive has so far resulted in the death of at least 460 Palestinians, including at least 100 civilians, according to UN estimates.
Israeli Foreign Minister Tzipi Livni said Thursday that Gaza is not facing humanitarian crisis.
"When women, children and babies are killed in Gaza, how can you say Gaza is not in a humanitarian crisis?" Christopher Gunness, a spokesperson for the UN relief operation in Gaza, told ABC News. "When hospitals are overwhelmed with patients, how can you not say Gaza is not in a humanitarian crisis? When bakeries are shut down, how can you say Gaza is not in humanitarian crisis?
"We are on the ground and we have a much better idea of the situation than those who view Gaza through the lenses of high-altitude bombers."
Asked whether the UN relief agency had succeeded in delivering food aid over the last 10 days of Israeli bombing, Gunness said: "We are continuing our food distribution, but it has been severely curtailed by the situation on ground."
A more detailed view of the food shortage situation emerged from the account of Maher Abu Dakka, a driver inside Gaza who spoke with ABC News in a telephone interview.
"We wait long hours, in long queues, in front of the bakeries to be able to buy bread," Abu Dakka said. "Shops are closed. Everything was shut down due to the air bombardments. There is no food and the only opened shops are running out of the basic food supplies. I have a 1-year-old son. No Pampers and constant shortages in baby milk. Nothing since last week. The windows glass was broken due to the bombardments. We can't even find plastic to seal the windows."
Before Saturday's Israeli invasion, Gaza was already the scene of a humanitarian emergency, owing to a crippling international embargo and strict Israeli blockade of the area, UN spokesperson Adnan Abu Hasna said.
"The conditions in Gaza were already miserable even before the Israeli air bombardments," said Abu Hasna. "We are talking about an area which is hard to describe.
"Gaza is a prison. No Palestinian is allowed to go out or to get in. Eighty percent of Gaza's population are refugees and non-refugees who rely on the UN aid. We are talking about an area where 750,000 Palestinian refugees depend entirely on food aid offered by the UN agencies. We are talking about an over 50 percent unemployment rate. What is happening in Gaza now surpasses the capacities of any humanitarian organization."
Abu Hasna said that in recent days Israel has allowed hundreds of tons of food aid and medicine into the Gaza strip and that the UN had begun distributing the food aid. It was not enough, however, he said, because "We are talking about hundreds of thousands of Palestinians."
In addition, the logistical challenges of delivering the food are great, he said.
"The situation on ground is grave, roads have been cut off," he said. "There are aerial bombardments which makes it very hard for the vehicles loaded with aid to move around"
Abu Hasna said that due to the blockade imposed on Gaza by Israel, Gaza residents typically received only 7 hours of electricity a day. When the Israeli aerial bombardment started last Saturday, the electricity flow was reduced to five hours a day. Gaza is now in complete dark.
"There is no electricity and when you don't have electricity, you will not have water and this makes people's life more difficult than what they are already," he said.
Gaza's hospitals were already in critical condition before the Israeli invasion, and the influx of thousands of wounded has deepened the crisis. In Gaza's Shifa hospital, temporary intensive care units for emergency surgeries have had to be improvised.
In live pictures from the hospitals Saturday, bleeding women, men and children lay on floors as they waited to be moved to already-occupied tables and treated.
Abu Hasna says that Gaza hospitals "lack everything from specialized doctors to intensive care units to operation rooms.
"They cannot cope with such number of killed and injured people."
Before the ground offensive, a lucky few of the injured were getting out and into Egypt to get emergency medical care.
On Sunday, the border crossing was closed. Not even the wounded were allowed out, and help wasn't allowed in.
''We are doctors, we want to go into Gaza but they wont let us in, the Egyptians," said Dr. Nicolas Dousis-Rassias of Doctors of Peace as he stood at the border. "Won't let us in.''
A long line of trucks carrying food and medicine from Arab countries at the border just waits.
The Egyptian government is under pressure to open the border fully, so civilians can get to safety.
Egypt says it is following instructions from the Israel, because opening the border would be too dangerous.
With reporting by ABC News' Lama Hasan in Egypt.