U.N. calls Israeli evacuation orders in Gaza "complete disaster" for humanitarian work as polio vaccinations set to begin

As the United Nations prepared to begin a polio vaccination campaign in the Gaza Strip Tuesday, a U.N. humanitarian worker there said multiple evacuation orders by the Israeli military have been "completely disruptive to the humanitarian response on the ground."

"If the humanitarians are having to move themselves, they're not able to work. Operations have to halt while they relocate," Louise Wateridge told CBS News partner network BBC News.

She said UNRWA, the U.N. agency that works in the Palestinian territories and is the largest primary health care provider in the Gaza Strip, had been ordered to evacuate its facilities at least 15 times in August so far — amounting to around once every two days.