Gaza City (Palestinian Territories) (AFP) – A crush at an aid centre in southern Gaza killed at least 20 people on Wednesday, with the site's operator blaming "Hamas operatives" within the crowd and the Palestinian territory's civil defence agency attributing the panic to Israeli gunfire.

AFP footage showed lifeless bodies taken to a nearby hospital in the city of Khan Yunis, with some placed on the floor and others on already-bloodied beds.

Abdullah Alian, a witness, said that mayhem unfolded as the crowd of aid-seekers was hit with stun grenades and pepper spray.

"When they saw people starting to die on the ground and people on top of each other suffocating, they opened the gate and people started climbing on top of each other."

It was not clear whether he was referring to US contractors securing GHF sites, Israeli forces or another party.

Paramedic Ziad Farhat said that after more than 21 months of devastating war, "there are not enough hospitals for the injured or the martyrs".

"Enough of the tragedies that we are living."

The GHF said that 19 of those killed on Wednesday "were trampled and one was stabbed amid a chaotic and dangerous surge".

Spokesman Chapin Fay later told a briefing that the deadly incident was "instigated by armed Hamas operatives who infiltrated a civilian crowd and deliberately incited chaos".

He denied the use of tear gas or that shots were fired into the crowd.

"Limited use of pepper spray was deployed only to protect against additional loss of life," Fay said, adding that "warning shots were fired into the air at one point when GHF personnel identified that a child was being trampled".

Gaza's civil defence agency said at least 20 people were killed in the incident, blaming it on fire from Israeli troops.

Agency spokesman Mahmud Bassal told AFP that thousands had gathered at the site when "Israeli forces opened fire and used (tear) gas, causing panic and a stampede after aid centre guards closed the main gates in front of the hungry crowd".

The Israeli military did not respond to a request for comment.