Israel has refused to renew visas for the heads of at least three United Nations agencies in Gaza, which the U.N. humanitarian chief blames on their work trying to protect Palestinian civilians in the war-torn territory.

Visas for the local leaders of the Office for the Coordination of Humanitarian Affairs, known as OCHA; the human rights agency OHCHR; and the agency supporting Palestinians in Gaza, UNRWA, have not been renewed in recent months, U.N. spokesman Stephane Dujarric confirmed.