The Israeli human rights group B’Tselem released a report Thursday saying that the majority of Palestinians killed in last November’s Operation Pillar of Defense in the Gaza Strip were civilians.

According to the watchdog’s report, 167 Palestinians were killed during the operation. Sixty-nine of those were combatants, of which seven were targeted in pinpoint airstrikes. Of at least 87 civilians killed, B’Tselem said, 20 were children under the age of 12. According to the report, it is unclear whether or not the remaining 11 Palestinians killed during the operation were combatants.

The Israeli offensive was launched on November 14 in response to ongoing rocket fire from the Hamas-controlled Gaza Strip into Israel. Over the course of eight days, some 1,500 airstrikes targeted terrorists in Gaza.

B’Tselem said that in the second half of the operation, the number of Palestinian casualties increased dramatically, with 119 deaths in the final four days, as opposed to 48 in the first four. Seventy of the 87 noncombatants were killed in the second half of the operation.

In the last four days of the operation, the ratio of civilian casualties grew considerably: Seventy noncombatants were killed as opposed to 17 in the first four days.

The report acknowledged that the IDF offensive was much more constrained and focused, and caused far fewer casualties, than Operation Cast Lead in 2009. However, the report stressed, the unprecedented number of civilian casualties during Cast Lead cannot be used a yardstick to determine whether the IDF acted lawfully during Pillar of Defense.

While the IDF said families of Hamas operatives were warned before airstrikes on their homes, B’Tselem said that the warnings were not given far enough in advance, and that the IDF failed to ascertain that the homes had in fact been evacuated before bombing them.

Moreover, charged B’Tselem, the homes of Hamas operatives are not legitimate targets, particularly not when family members live in them.

“B’Tselem’s report raises suspicions that the military violated International Humanitarian Law (IHL). Breaches of two major aspects of IHL are of greatest concern: lack of effective advance notice of an impending attack and an unacceptably broad definition of what constitutes a ‘legitimate target,'” the group said in a statement.

Responding to the report, the IDF attributed the majority of noncombatant deaths to the fact that terror organizations operated from within civilian areas. There were also a few cases in which, according to the IDF, civilians were mistakenly identified as terror operatives.

The report also cited the killing of four Israeli civilians and two IDF soldiers killed during Operation Pillar of Defense and acknowledged that Hamas broke the laws of war by operating from within a civilian areas. Such conduct on the part of Hamas, however, “cannot serve as justification for IHL violations by the Israeli military,” the report said.

“Immediately after the operation was completed, a committee was formed by the chief of staff… and the military advocate general began checking procedural violations by IDF soldiers during the operation,” said the IDF spokesperson said in response. “In cases whose investigation has been completed, the military advocate general did not find justification for criminal investigations.”

The army asserted that “by and large,” it had “conducted itself with consummate professionalism and prudence.”

Israel-based watchdog NGO monitor issued a fierce response to the publication of the report, claiming that B’Tselem used flawed methods as a basis to reach its conclusions.

“The press statement claims that the ‘report raises suspicions that the military violated International Humanitarian Law’,” read a statement released by the organization. “But these allegations are not demonstrated in the report; at best, they are the result of conjecture, as B’Tselem itself acknowledges in the report. Additionally, the claim to distinguish between civilian and combat deaths in this report, as in past B’Tselem statements, is based on manipulated definitions and speculation, and the application of existing legal standards would result in very different conclusions.”