In fighting Islamic State combatants in Iraq, US troops used an Israeli tactic designed to reduce civilian casualties during bombardments.
Known as “roof knocking,” it involves hitting buildings suspected as occupied by residents with a non-lethal projectile to warn civilians shortly before an incoming bombardment on the building tapped.
US troops used it in the Iraqi city of Mosul this month, but a woman was killed in the attack, Air Force Major General Peter Gersten, deputy commander for operations and intelligence for the U.S.-led coalition, said on Tuesday, according to Reuters.
The Israeli military used such “roof knocks” in the 2014 Gaza war on Hamas but a United Nations commission found in 2015 that the tactic was not effective because it often caused confusion and did not give residents enough time to escape.
The United States used the tactic in an April 5. One woman who initially did leave the targeted building but then ran back inside was killed, Gersten said in a press conference in which he spoke remotely over a video uplink to listeners, including journalists, at the Pentagon during a Defense Department briefing.
The building housed a member of Islamic State, or ISIS, in charge of distributing money to fighters, as well as being a cash storage site, he said.
U.S. intelligence and reconnaissance aircraft tracked the site and observed that a woman and children also frequented the house, which the United States believed to contain about $150 million.
Looking to ensure they and any other non-combatants were clear of the building, the military turned to a tactic used by the Israeli Defense Forces in some of its operations against Hamas militants, Gersten said.
The plan consisted of firing a Hellfire missile above the building “so it wouldn’t destroy the building, simply knock on the roof to ensure that she and the children were out of the building,” he said.
“We’ve certainly watched and observed their procedure,” Gersten said of the Israelis, while noting that the military did not coordinate with the Israelis on the strike. “As we formulated the way to get the civilians out of the house, this (technique) was brought forward from one of our experts.”
The U.S.-led coalition could employ the roof knock technique again in the future, he said. The U.S. military acknowledges killing 41 civilians so far in its air campaign against ISIS, which began in 2014.