U.N.: Israeli ‘Roof-Knocks’ Did Not Provide Effective Warning to Gaza Civilians

Israeli officials argue the novel warning strikes were aimed at mitigating civilian casualties during last year's Gaza war.


When Israeli forces in the summer of 2014 launched aerial and ground operations against militants in Gaza, they employed what was a novel approach of notifying civilians of an imminent air strike. That technique was called a “knock on the roof” and involved striking a building — typically its roof — with a small munition prior to the larger, main strike. Now, a new United Nations report concludes that roof-knocks were not an effective method of warning civilians of an incoming strike.

That finding is part of a 183-page report issued Monday by the United Nations Human Rights Council, which finds that both Israeli forces and Palestinian militants may have committed war crimes in an armed conflict that saw large parts of Gaza leveled by Israel Defense Forces in pursuit of Gazan militants firing rockets into Israeli territory. The report concludes that the use of such weapons by Hamas and other militant groups likely constituted a war crime, as the inaccurate weapons are indiscriminate and fail to distinguish between military and civilian targets. By the same token, the report argues that Israeli forces used excessive force and failed to take adequate measures to protect civilian life in attempting to stop those rocket firings.

Throughout the conflict, however, Israeli officials maintained that they were going to extraordinary lengths to protect human life and frequently cited roof-knocks as a prime example of their dedication to sparing civilian life. The tool was a fairly novel development in the history of warfare and appeared to be, at least on its face, an innovative way to save lives. But the U.N. report offers a withering assessment of roof-knocks.

In order for a warning to civilians to be considered adequate, the report argues that such a warning must be intelligible to its intended audience and for the civilians to have the ability to act on the warning. But Gaza residents interviewed by the report’s authors frequently did not understand that their house had been subjected to a roof-knock. In the dense urban environment of the Gaza Strip, residents frequently did not know whether it was their house that it had been struck with a warning missile. In an atmosphere of frequent aerial attacks, a minor explosion was sometimes confused as a distant strike. Other families left their house after a warning strike only to be hit by a missile once they had gone outside.

The IDF video below illustrates how the practice works and also sheds light on the limitations of the roof-knock to mitigate civilian casualties. It shows how civilians flee a building targeted by a warning strike. According to the IDF, other civilians then flock to the building to act as human shields.

“In an area with buildings all around, how can the recipient of such a ‘roof-knock’ know which building he or she should avoid if this is not specified in the message?” the report asks. “Based on the warning that a building close to one’s own will be targeted, while a person may be willing to leave the house, he or she cannot know in what direction to escape.”

To be sure, aspects of the technique remain shrouded in the fog of war. Israeli officials have said that the technique of roof-knocks were typically used in concert with other warnings — the use of phone calls and flyers, for example. The report acknowledges being “unable to verify whether ‘roof-knocking’ was systematically combined with other warnings and whether there were cases in which ‘roof-knocking’ was the only form of specific – and ambiguous – warning civilians received.”

Taken as a whole, the report makes for awful reading and is unsparing in its criticism of both sides, though Israel on Monday denounced the document as hopelessly biased while Hamas cheered it and said it should serve as the basis of war crimes prosecutions. The report includes testimony from both Israelis and Palestinian civilians about the war’s effects on themselves and their communities. The sections devoted to fighting in Gaza include heartbreaking accounts of civilians seeing family members dismembered by high-powered bombs. The accounts of rocket and mortar strikes in Israel include devastating testimony from parents who lost children in militant attacks.

That human suffering was not relieved by the use of roof-knocks, the U.N. has concluded.


Elias Groll is a staff writer at Foreign Policy. Twitter: @EliasGroll

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