NEW : Doctor : Some 80 percent of the injured people dead at hospital are children . NEW : At least 507 people have been killed in the military operation . An official with the humanitarian group World Vision also confirmed that report , saying : `` Unfortunately today , they closed the border , so no aid entered Gaza today . '' Doctor : ` ` people were killed before they received treatment '' Some 25 baggage bearing passengers could not cross the Gaza - Egypt border on Sunday .
NEW : Doctor : Some 80 percent of the injured people dead at hospital are children . NEW : At least 507 people have been killed in the military operation . Doctor : ` ` people were killed before they received treatment '' Some 25 baggage bearing passengers could not cross the Gaza - Egypt border on Sunday .