Mass casualty incidents caused by the Israeli military offensive in southern Gaza are becoming normalised in the west and leading to a sense of fatalism inside Gaza itself, according to Sam Rose, the director of planning for the Palestinian relief agency Unrwa.

He was speaking after an Unrwa school at Nuseirat was bombed by Israeli forces leaving at least 33 dead, including 12 women and children.

“When everyone is living in cramped, overcrowded conditions, we always said it would be inevitable that there would be incidents such as the one that happened overnight in the school in Nuseirat.”

Rose, who had just returned to London after five weeks in Gaza, said: “There were about 6,000 people sheltering in that school. There are rules of war that we call on all sides of the conflict to adhere to: to protect the inviolability of our installations. There are also principles of distinction, and of proportionality.

“People will have been sheltering in the courtyard of the school in the most desperate of conditions and there will have been no warning that this strike has taken place. It happened in the middle of the night about 2am.