Some 800,000 people have been forced to flee Gaza's southernmost town of Rafah since Israel launched a military operation in the area in early May, the head of the UN agency for Palestine refugees (UNRWA) said on Saturday, urging greater protection for civilians in Gaza, safe humanitarian access and a ceasefire. The renewed appeal comes as virtually no aid has entered Gaza for more than ten days, and essentials such as fuel, food and water are in dangerously short supply.