UN aid chief Tom Fletcher said in a post on X that the bodies were buried near "wrecked & well-marked vehicles," adding: "They were killed by Israeli forces while trying to save lives. We demand answers & justice."
Israel's military did not comment directly on the deaths of the Red Crescent workers.
In a later statement to Reuters, it said that it had facilitated the evacuation of the bodies from the area, which it described as an active combat zone. It did not specifically respond to questions about why the bodies were retrieved beneath the sand nor why the vehicles were found crushed.
Philippe Lazzarini, head of the UN agency for Palestinian Refugees (UNRWA), said on social media platform X that the bodies had been "discarded in shallow graves - a profound violation of human dignity".
Lazzarini said the deaths brought the total number of aid workers killed since the onset of the Israel-Hamas war in Gaza to 408.
In a statement late on Sunday, the International Committee of the Red Cross said it was "appalled" at the deaths.
"Their bodies were identified today and have been recovered for dignified burial. These staff and volunteers were risking their own lives to provide support to others," it said.
The International Federation of Red Cross and Red Crescent Societies (IFRC) said one worker from the nine-strong Red Crescent group was still unaccounted for. It did not immediately comment on the details of the site where the bodies were found. The group went missing on March 23 to tend to the injured in Rafah, after Israel resumed an all-out offensive against Hamas.
The Palestine Red Crescent said it also recovered the bodies of six civil defence members and one UN employee from the same area. It said Israeli forces had targeted the workers. Red Cross statements did not apportion blame for the attacks.
The Israeli military said on Monday that an inquiry had found that on March 23, troops opened fire on a group of vehicles that included ambulances and fire trucks when the vehicles approached a position without prior coordination and without headlights or emergency signals.
It said several militants belonging to Hamas and Islamic Jihad were killed.
"The IDF condemns the repeated use of civilian infrastructure by the terrorist organizations in the Gaza Strip, including the use of medical facilities and ambulances for terrorist purposes," it said in a statement.
MOUND OF SAND
Jonathan Whittall, Gaza head of the UN Office for the Coordination of Humanitarian Affairs (OCHA), described the site where the bodies were found as a "mass grave", saying it had been marked with the emergency light from a crushed ambulance.
His comments on X were accompanied by pictures of Red Crescent teams digging in the sand for the bodies next to a mangled fire truck and a UN vehicle.
An OCHA spokesperson said in response to Reuters questions that the burial site resembled a large mound of sand which was "clearly created by a bulldozer or similar machinery rather the impact of a blast."
"The available information indicates that the first team was killed by Israeli forces on 23 March, and that other emergency and aid crews were struck one after another over several hours as they searched for their missing colleagues," the spokesperson added.
The incident was the single most deadly attack on Red Cross or Red Crescent workers anywhere since 2017, the IFRC said.
"I am heartbroken. These dedicated ambulance workers were responding to wounded people. They were humanitarians," said IFRC Secretary General Jagan Chapagain.
"They wore emblems that should have protected them; their ambulances were clearly marked," he added.
According to the United Nations, at least 1,060 healthcare workers have been killed in the 18 months since Israel launched its offensive in Gaza after Hamas fighters stormed southern Israel on October 7, 2023.
Due to safety concerns, the UN is reducing its international staff in Gaza by a third.
