The fuel crisis in Gaza is so dramatic that trucks filled with aid arriving through the Rafah crossing from Egypt won't be unloaded starting Tuesday because there is no fuel for the forklifts, or for vehicles to deliver the food, water and medicine they're carrying to those in desperate need, a senior U.N. humanitarian official says.

Andrea De Domenico, the U.N. humanitarian coordinator for the Palestinian territories, said "lives in Gaza are hanging by a thread due to the bleeding of fuel and medical supplies." And he said since Israeli troops arrived in Gaza City center five days ago, it has been too dangerous for the U.N. to coordinate any operation in the north.

De Domenico said in a video press conference with U.N. correspondents from east Jerusalem that the intensified fighting over the weekend around Shifa hospital, the biggest in Gaza City, damaged critical infrastructure including water tanks, oxygen stations and the cardiovascular facility in the maternity ward. Three nurses were reported killed, he said.