The White House has condemned an attack on an aid convoy heading to Gaza by Israeli settlers who threw packages of food into the road and set fire to the vehicles.

Video of the incident on Monday at Tarqumiya checkpoint, west of Hebron in the Israeli-occupied West Bank, showed settlers blocking the trucks and throwing boxes of much-needed supplies on the ground. Photographs from the scene showed piles of damaged aid packages and drifts of rice and flour across the road.

Late on Monday, photos began circulating on social media showing the trucks on fire.

Israel has faced heavy international pressure to step up the flow of aid into Gaza, where international organisations have warned of a severe humanitarian crisis threatening a population of more than 2 million people.

“It is a total outrage that there are people who are attacking and looting these convoys coming from Jordan, going to Gaza to deliver humanitarian assistance,” US national security adviser Jake Sullivan told reporters.

“We are looking at the tools that we have to respond to this,” he added. “We are also raising our concerns at the highest level of the Israeli government and it’s something that we make no bones about – this is completely and utterly unacceptable behaviour.”

Referring to a US report issued on Friday on Israeli compliance with international humanitarian law, Sullivan said that the Israeli state had hindered aid deliveries in the recent past but had improved the flow sufficiently, so as not to be subject to restrictions on military aid that might have been required under US law.

“We believe that there were periods over the last few weeks where there were restrictions that had to be worked through,” Sullivan said. “But at the time we put that report forward, we felt that there was sufficient work being done by the Israeli government with respect to the facilitation of humanitarian aid, that we did not make a judgment that anything had to be done in terms of US assistance.”

Police do not appear to have intervened to stop the looting, though four people including a minor were later reported to have been arrested.

This is not the first time that settlers have tried to stop the flow of aid to Gaza, which is already only a fraction of that needed by the population of the embattled territory.

Last week, Israeli demonstrators blocked a road near the desert town of Mitzpe Ramon to protest against the delivery of aid trucks into the strip. The protesters – who say the aid is helping Hamas and want to block its passage until all Israeli hostages are freed – formed a sit-in protest as they scattered rocks across the road to prevent vehicles from passing, creating standstill traffic.

Israel’s siege of Gaza has created what aid officials are referring to as “man-made starvation”, with the territory facing the threat of mass deaths from famine with children already dying from hunger.

In March, the international court of justice ordered Israel to allow unimpeded access of food aid into Gaza, where sections of the population are facing imminent starvation.

Aid efforts have been further complicated by the temporary closure of the headquarters of the main channel for humanitarian support for Palestinians after weeks of violent protests and arson attacks by Israeli right-wingers.

The UN agency for Palestinian refugees announced it was closing its East Jerusalem headquarters on Thursday after a fresh attack by what Philippe Lazzarini, the head of the agency, described as “Israeli extremists”.