"Canned meat is a major part of our food parcels, and is the only source of protein in the UNRWA food package," Christopher Gunness, an UNWRA spokesman told IRIN.

"The trucks can't get through because of the snow," said Moshe Krief, a spokesman for the Israeli Ministry of Defence, noting the somewhat rare -- and heavy -- snowfall in Jerusalem and the surrounding area.

However, aid workers said the snowstorm had been expected, and that the trucks should have been allowed to move in over the past few days, before the weather made it impossible.

The ban on the entry of commercial trucks, in effect since 18 January, continued this week, adding to a shortage of available supplies of protein-rich foods. Even fishing off Gaza's coast is restricted.

"If the canned meat doesn't get in today [30 January], people [receiving UNRWA food parcels] won't have protein in their diets tomorrow," Gunness said.

The four lorries with the UNRWA meat were being held up in the West Bank.

UNRWA feeds about 860,000 Palestinian refugees a day and the World Food Programme (WFP) provides for about 300,000 people, out of a total population of about 1.5 million in the Gaza Strip. However, their aid packages can only meet 65 percent of food needs, making commercial imports vital.

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