Food and medicine for Palestinians in the Gaza Strip are piling up in Egypt because the Rafah crossing remains closed and there has been no aid delivered to a U.N. warehouse from a U.S.-built pier for two days, U.N. officials warned on Monday.

Senior U.N. aid official Edem Wosornu said there were insufficient supplies and fuel to provide any meaningful level of support to the people of Gaza as they endure Israel's military onslaught against Hamas militants.

"We are running out of words to describe what is happening in Gaza. We have described it as a catastrophe, a nightmare, as hell on earth. It is all of these, and worse," she said.