The United States has carried out the first of what it said would be a series of humanitarian airdrops of food into Gaza, as aid agencies warned of a growing humanitarian disaster in the Palestinian enclave in the absence of a ceasefire deal.

Three C-130 US military planes delivered more than 38,000 meals into a territory where the United Nations says at least 576,000 people are one step away from famine conditions.

Palestinians posted videos on social media showing boxes of aid being dropped. Jordanian forces also participated in the operation, Reuters reports.

The White House has said the airdrops would be a sustained effort, and that Israel supports them. Critics say airdrops are far less effective than aid deliveries by truck, and it is nearly impossible to ensure supplies do not end up with militants.

“Israel welcomes the humanitarian airdrops by the US, which were discussed and coordinated with us,” said an Israeli official in Washington, speaking on condition of anonymity.