The UN aid chief said Wednesday that recent "horrifying scenes" of Gazans being killed while seeking food aid were the result of "deliberate choices that have systematically deprived" them of essentials to survive.
A US and Israeli-backed group operating aid sites in the Gaza Strip announced the temporary closure of its facilities on Wednesday, with the Israeli army warning that roads leading to distribution centers were "considered combat zones".
The announcement by the Gaza Humanitarian Foundation follows a string of deadly incidents near the distribution sites it operates.
On Tuesday, 27 people were killed in southern Gaza when Israeli troops opened fire near a GHF aid site, with the military saying the incident was under investigation.
"The world is watching, day after day, horrifying scenes of Palestinians being shot, wounded or killed in Gaza while simply trying to eat," UN humanitarian chief Tom Fletcher said in a statement.
"Emergency medical teams have confirmed treating hundreds of trauma cases. Yesterday alone, dozens were declared dead at hospitals after Israeli forces said they had opened fire.
"This is the outcome of a series of deliberate choices that have systematically deprived two million people of the essentials they need to survive."
He echoed the call by UN chief Antonio Guterres for immediate independent investigations, saying they were not isolated incidents, and the perpetrators must be held accountable.
"No-one should have to risk their life to feed their children," said Fletcher.
The GHF began operations a week ago, but the UN and major aid groups have refused to cooperate with it over concerns it was designed to cater to Israeli military objectives.
Meanwhile the United Nations has described the amount of aid allowed into Gaza, after Israel partially lifted a more than two-month total blockade, as a trickle.
"We must be allowed to do our jobs: we have the teams, the plan, the supplies and the experience," said Fletcher, the UN under-secretary-general for humanitarian affairs and emergency relief coordinator.
"Open the crossings -- all of them. Let in life-saving aid at scale, from all directions. Lift the restrictions on what and how much aid we can bring in.
"Ensure our convoys aren't held up by delays and denials. Release the hostages. Implement the ceasefire."