In the four weeks since the launch of a controversial US- and Israeli-backed aid system in Gaza, there have been repeated incidents of killings and injuries of Palestinians seeking aid.

According to the Hamas-run Gaza health ministry, in the past month more than 500 people on their way to get aid have been killed and 4,000 injured.

To get a clearer understanding of how the last month has unfolded, BBC Verify has analysed dozens of videos from across Gaza that offer an insight into what this aid system looked like on the ground. Footage shows a near-daily cycle of chaos, panic, live gunfire and dead or injured Palestinians.

While the videos show an overall picture of danger and chaos, they do not definitively show who is responsible for firing in each incident. However in many cases, eyewitnesses and medics have described Israeli forces opening fire on crowds near aid sites.

In statements over the past month, the Israel Defense Forces (IDF) have several times said they fired “warning shots” at individuals who they described as “suspects” or said posed a threat.

The IDF has told BBC Verify that Hamas does “everything in its power to prevent the success of food distribution in Gaza, tries to disrupt aid, and directly harms the citizens of the Gaza Strip”.

On 18 May Israel announced it was partially easing its 11-week long blockade of aid into Gaza, which it had said was aimed at putting pressure on Hamas to release hostages.

The IDF built four aid distribution sites – three in the far south-west of Gaza and one in central Gaza by an Israel security zone known as the Netzarim Corridor – which began operations on 26 May.

These sites in IDF-controlled areas – known as SDS 1, 2, 3 and 4 – are operated by security contractors working for the Gaza Humanitarian Foundation (GHF), with the Israeli military securing the routes to them and the perimeters. On Thursday the US State Department announced $30m (£22m; €26m) in funding for the GHF – the first known direct contribution to the group.

From the start the UN condemned the plan, saying it would “militarise” aid, bypass the existing distribution network and force Gazans to make long journeys through dangerous territory to get food.

Within days of the plan starting, dozens of Palestinians were killed in separate incidents on 1 and 3 June, sparking international condemnation. Since then there have been near-daily reports of killings of people travelling to collect aid.

The IDF said that its “forces conduct systematic learning processes aimed at improving the operational response in the area and minimizing possible friction between the population and the IDF forces”.

Israeli government spokesman David Mencer called reports of people killed while getting aid “another untruth”. “There have not been hundreds of people dying.”

The GHF denied there had been any “incident or fatalities at or near” any of its distribution sites.

On Tuesday, the Red Cross said its field hospital in Rafah had had to activate its mass casualty procedures 20 times since 27 May, with the vast majority of patients suffering gunshot wounds and saying they had been on the way to an aid site.

The UN and its World Food Programme as well as other aid providers are continuing to try to distribute aid in Gaza, but they say they are reliant on the Israeli authorities to facilitate their missions.

The UN’s Office of the High Commissioner for Human Rights said the killing of Palestinians trying to access aid was a “likely war crime”. International human rights lawyer Sara Elizabeth Dill told BBC Verify that if there had been any intentional targeting of civilians, it could constitute a serious violation of international law.

“Mass shootings during civilian relief access violate core rules against targeting civilians and using starvation against them, potentially rising to war crimes,” she said.

Three videos, the first of which was published on 9 June, showed hundreds of people, some holding what appear to be empty flour sacks, scrambling over mounds of rubble and hiding in ditches. Several bursts of automatic gunfire can be heard.

On that day, the Hamas-run health ministry reported six people had been killed that morning while seeking aid and more than 99 injured. The next day, it reported 36 aid-related deaths and more than 208 injuries.

It’s not possible to verify whether any of these casualties were a result of the gunfire that could be heard in the footage.

We were able to confirm the videos were filmed from about 4km (2.5 miles) north-west of SDS4, on the way to the site in central Gaza.

Audio analysis of the gunfire from Steve Beck, a former FBI consultant who now runs Beck Audio Forensics, said one of the guns sounded like and fired at rates consistent with the FN Minimi machine gun and the M4 assault rifle. The second gun, Mr Beck said, fired at a rate that was “compatible” with the sound of an AK-47. We cannot establish whose weapons were firing but FN Minimis and M4s are commonly used by the IDF, while AK-47s are typically used by Hamas and other groups in Gaza.

In footage published the next day, on 10 June, and filmed nearby, more crowds were seen running in panic as the sound of gunfire, followed by what sounds like an explosion, was heard in the distance. Injured and bloodied people, including children, were then seen being carried away.

GHF has maps showing “safe passages” to its sites and communicates opening times via WhatsApp and social media.

Each passage has a “start point” and a ”stop point” with Palestinians warned that they must not cross the latter until instructed. The GHF has said these corridors are secured by the IDF and warned people that crossing these stop points, unless told to, may be dangerous.

But at SDS4 there was no safe passage planned for people coming from the north.

There have also been killings close to non-GHF related aid sites.

Verified footage from 17 June showed at least 21 bodies and several injured people on a road in which several vehicles, including a heavily damaged flatbed truck, were parked.

Witnesses told the BBC that IDF drones and a tank fired at the crowd as they were waiting to collect aid.

An IDF statement acknowledged that it had identified a “gathering” of people “adjacent to an aid distribution truck that got stuck in the area of Khan Yunis, and in proximity to IDF troops operating in the area”.

It said: “The IDF is aware of reports regarding a number of injured individuals from IDF fire following the crowd’s approach.” It expressed regret for “any harm to uninvolved individuals” and said the details of the incident were under review.

A spokesman for Gaza’s Hamas-run civil defence agency said at least 50 people were killed at the scene.

The video shows a number of the dead around scorch marks on the ground, including one person with their legs blown off.

Mark Cancian, from the Centre for Strategic and International Studies, noted the lack of obvious impact crater but told us the extent of damage was likely the result of “a lot of direct fire”.

Another video posted on 16 June, which we’ve verified, shows bodies pulled on a cart by a horse along al-Rashid street in northern Gaza, the main coastal road and often used by aid convoys.

The caption alongside the video claims that these Palestinians were killed while waiting for aid.

The next day, several photos and videos we verified were posted on social media located nearby showing a body carried by several men on a wooden pallet along the same road.

The GHF claimed many of the alleged incidents were linked to convoys and distribution sites for other groups, including the UN. It said those aid supplies were “being looted by criminals and bad actors”.

A GHF spokesperson said it has overall been “pleased” with its first month of operations, with 46 million meals distributed to two million Gazans, but was aiming to scale up its capacity.

The IDF has said that among other changes it is installing fences and signs and opening additional routes.

“We have raised concern [with the IDF] about maintaining safe passage for aid seekers but unfortunately some have attempted to take dangerous short cuts or travel during restricted times,” the GHF spokesperson said.

“Ultimately the solution is more aid, which will create more certainty and less urgency among the population.”

Additional reporting and verification by Paul Brown, Emma Pengelly, Lamees Altalebi, Richard Irvine-Brown, Benedict Garman, Alex Murray, Kumar Malhotra, and Thomas Spencer.