The World Health Organization on Wednesday warned that an Israeli military offensive against Rafah in southern Gaza would cause an "unfathomable catastrophe" and push the territory’s health system closer to the brink of collapse.

"Military activities in this area, this densely populated area, would be, of course, an unfathomable catastrophe... and would even further expand the humanitarian disaster beyond imagination," said Richard Peeperkorn, WHO representative for Gaza and the West Bank, Reuters reported. 

Peeperkorn said WHO's ability to distribute medical aid to Gaza was limited because many of its requests to deliver supplies had been denied.

More than one million Palestinians crammed into Rafah at the southern tip of the Gaza Strip, on the border with Egypt, where many are living in tent camps and makeshift shelters after fleeing Israeli bombardments elsewhere in Gaza.