Israeli tank and gunfire was heard Tuesday while giant crowds of Palestinians tried to reach a newly opened aid distribution centre in southern Gaza, according to reports from CBC News and The Associated Press journalists.

Witnesses said chaos erupted as desperate people broke through fences at the centre, forcing staff to retreat.

The Israeli military said its troops fired the warning shots in the area outside the centre and that "control over the situation was established." 

At least three injured Palestinians were seen by the AP being brought from the scene, one of them bleeding from his leg. 

The turmoil came on the second day of operations by a U.S.-backed group, the Gaza Humanitarian Foundation (GHF), which Israel has slated to take over food distribution in Gaza, despite opposition from the United Nations and other humanitarian organizations. 

Palestinians have become desperate for food after nearly three months of Israeli blockade, which has pushed Gaza to the brink of famine according to the World Health Organization. On Tuesday, hundreds of thousands of men, women and children walked for several miles, through Israeli military lines, to reach the GHF distribution hub set up on the outskirts of Rafah. 

In the afternoon, the AP journalist, positioned some distance from the hub, heard tank and gun fire and saw a military helicopter firing flares. Smoke could be seen rising from where one round impacted. Afterwards, crowds were seen returning from the site, almost all of them without having received aid.

CBC News freelance videographer Mohamed El Saife, who was at the scene, said gunshots were fired into the air and the water but did not appear to injure anyone.

There was no immediate comment from the Israeli military.

Ahmed Abu Taha, who was among those seeking aid, said crowds of people stormed into the distribution centre, breaking fences. He heard gunfire and saw Israeli military aircraft overhead, "It was chaos," he said. "People were panicked."

Another Palestinian, Saleh Abu Najjar, said he heard a tank firing from a distance, east of the centre. "The situation was very dangerous and people were frightened," he said. 

8,000 food boxes handed out so far: GHF

In a statement, GHF said that because of the large number of Palestinians seeking aid, staff at the hub followed the group's safety protocols and "fell back" to allow them to dissipate, then later resumed operations. 

"What happened today is conclusive evidence of the occupation's failure to manage the humanitarian crisis it deliberately created through a policy of starvation, siege, and bombing," the Hamas-run government media office said in a statement.

GHF uses armed private contractors to guard the hubs and the transportation of supplies. The hub is also close to Israeli military positions in the Morag Corridor, a band of territory across the breadth of Gaza that divides Rafah from the rest of the territory.

GHF has set up four hubs around Gaza to distribute food, two of which began operating on Monday — both of them in the Rafah area. UN officials and aid workers have warned of the risk of frictions between Israeli troops and crowds of people seeking aid at the hubs.

By late afternoon on Tuesday, the GHF said it had distributed about 8,000 food boxes, equivalent to about 462,000 meals.

Some of the recipients showed the content of the packages, which included some rice, flour, canned beans, pasta, olive oil, biscuits and sugar.

Although the aid was available on Monday, Palestinians appeared to have heeded warnings, including from Hamas, about biometric screening procedures employed at the foundation's aid distribution sites.

"As much as I want to go because I am hungry and my children are hungry, I am afraid," said Abu Ahmed, 55, a father of seven.

"I am so scared because they said the company belongs to Israel and is a mercenary, and also because the resistance [Hamas] said not to go," he said in a message on the chat app WhatsApp.