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 Palestine Red Crescent said it also recovered the bodies of six civil defence members and one U.N. employee from the same area. It said Israeli forces had targeted the workers. Red Cross statements did not apportion blame for the attacks.
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. The group went missing on March 23.
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 the militant groups 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.
It did not comment directly on the deaths of the Red Cross workers.
The incident was the single most deadly attack on Red Cross 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.
The global body is reducing its international staff in Gaza by a third due to staff safety concerns.
(Writing by Dave Graham; Additional reporting by James MackenzieEditing by Aidan Lewis)

Plaestinians walk along Al Wihda street, close to Al Shifa hospital, in Gaza City, 25 March 2025. Israeli forces resumed airstrikes on Gaza on 18 March, ending a ceasefire that had been in place since 19 January. EPA-EFE/MOHAMMED SABER