AMMAN: The United Nations appealed on Thursday for urgent aid to help thousands of Syrian refugees in a Jordanian camp who are battling mud, water and freezing temperatures in the worst winter storm in a decade.

"The resources we raised in 2012 have been exhausted, and no fresh funds have come for this year. We urgently appeal to the international community and donors in general to commit fresh funding as soon as possible," UN Children's Fund (UNICEF) Jordan representative, Dominique Hyde said in a statement.

"The next 72 hours will be a critical test of our ability to meet the basic needs of children and their families at Zaatari" refugee camp in the desert near the Syrian border, Hyde added.

The Jordanian government and other partners, "are doing everything possible to ensure services are maintained and that children stay warm and dry," she said.

The seven-square-kilometre (2.8-square-mile) Zaatari camp, home to more than 62,000 Syrian refugees, was almost entirely inundated by water on Wednesday.

Heavy wind and rains knocked down at least 500 tents, which normally house five people, as camp residents elsewhere dug shallow trenches around their tents in a vain attempt to keep the water out.

"The deteriorating situation at Zaatari comes amid a continuing influx of refugees from across the border. Since the beginning of January, close to 10,000 Syrians have arrived in Jordan," UNICEF said.

Jordan says it is hosting around 290,000 Syrian refugees.

By Thursday, the weather was beginning to improve. The snowfall had stopped, but there were still some scattered showers.