Israeli air strikes that killed international aid workers in Gaza in April were the result of serious operational failures but were not intentional, according to an Australian government review of the incident, Reuters reports.

Three Israeli air strikes hit the convoy of aid vehicles travelling through Gaza on April 1, killing seven World Central Kitchen (WCK) staff. The dead included Palestinians and citizens of Australia, Britain and Poland.

An Australian review into the deaths said the Israel Defence Force (IDF) decided to launch missiles at the convoy after mistakenly believing it was being hijacked by Hamas fighters, who were in fact locally contracted security guards.

In addition, information about the WCK convoy’s movements had not reachedthe IDF team behind the strike, it said. This confusion was compounded because Israeli officials could not directly communicate with the aid convoy, the review added.

IDF staff also violated standard procedures in ordering the second and third strikes on the convoy without carrying out another identification process, it said.

“In this incident, it appears that the IDF controls failed, leading to errors in decision making and a misidentification, likely compounded by a level of confirmation bias,” according to Air Chief Marshal Mark Binskin, who travelled to Israel to investigate the deaths.

“Based on the information available to me, it is my assessment that the IDF strike on the WCK aid workers was not knowingly or deliberately directed against the WCK.” Israel’s investigation into the deaths had been “timely, appropriate and, with some exceptions, sufficient,” he said.