"But in the face of a ground offensive in Gaza, I plead that the sins of Hamas are not borne by the citizens of Gaza, who themselves have faced such suffering over many decades. The price of evil cannot be paid by the innocent. Civilians cannot bear the costs of terrorists," he said in a statement.

"Over two million civilians in Gaza, half of them children, are facing a catastrophe. A humanitarian corridor and convoy are needed as rapidly as possible, as set out in the Geneva Conventions."

(Reporting by Elizabeth Piper)