Israeli forces may have repeatedly violated fundamental principles of the laws of war and failed to distinguish between civilians and fighters in their Gaza Strip military campaign, the United Nations human rights office said on Wednesday.

In a report assessing six Israeli attacks that caused a high number of casualties and destruction of civilian infrastructure, the U.N. human rights office (OHCHR) said Israeli forces “may have systematically violated the principles of distinction, proportionality, and precautions in attack.”

“The requirement to select means and methods of warfare that avoid or at the very least minimise to every extent civilian harm appears to have been consistently violated in Israel’s bombing campaign,” said U.N. High Commissioner for Human Rights Volker Turk.

Israel’s permanent mission to the United Nations in Geneva characterised the analysis as “factually, legally, and methodologically flawed.”

“Since the OHCHR has, at best, a partial factual picture, any attempt to reach legal conclusions is inherently flawed,” the Israeli diplomatic mission said.

The report details six incidents that took place between Oct. 7 and Dec. 2, in which the U.N. human rights office was able to assess the kinds of weapons, the means and the methods used in these attacks.

“We felt that it was important to get this report out now, especially because in the case of some of these attacks, some eight months have passed, and we are yet to see credible and transparent investigations,” said Ravina Shamdasani, spokesperson for the U.N. human rights office.

“We call first on the Israeli authorities to take steps to ensure that proper investigations, transparent investigations are held.”

She added that, in the absence of transparent investigations, there would be “a need for international action in this regard as well.”

Israel’s air and ground offensive has killed more than 37,400 people in the Hamas-ruled Palestinian territory, according to health authorities there.

Israel launched its assault after Hamas fighters stormed across the border into southern Israel on Oct. 7, killing around 1,200 people and taking more than 250 people hostage, according to Israeli tallies.

Last week the U.N. human rights office said the killing of civilians during an Israeli operation to free four hostages could amount to war crimes, but so might Palestinian militants’ holding of captives in densely populated areas.