A United Nations official has broken down live on air as he talked about a deadly attack on a school in Gaza.

Chris Gunness wept uncontrollably as he discussed the Israeli shelling during an interview with Al Jazeera Arabic on Wednesday.

Addressing the camera, Gunness says, "The rights of Palestinians even their children, are wholesale denied… and it's appalling".

The Relief and Works Agency spokesman then bites his lip and clears his throat as he attempts to compose himself.

The interviewer appears to thank him and Gunness manages to utter the words, "My pleasure" before placing his head in his hands and sobbing.

Someone rushes over to comfort him and the camera pans away, though Gunness can still be heard weeping.