The Gaza Humanitarian Foundation said that it was unable to open its aid distribution centers in the Gaza Strip on Saturday due to threats from Hamas, in the latest disruption to the aid group’s operations as it struggles to get off the ground.

JERUSALEM (AP) — Israel is supporting armed groups of Palestinians in Gaza in what it says is a move to counter Hamas. But officials from the U.N. and aid organizations say the military is allowing them to loot food and other supplies from their trucks.

Gaza’s civil defence agency said Saturday that Israeli forces had killed at least 36 Palestinians, six of them in a shooting near a US-backed aid distribution centre. The Israeli military told AFP that troops had fired “warning shots” at individuals it said were “advancing in a way that endangered the troops”.