A Pentagon spokesman has revealed that the U.S. military is now adopting Israeli military tactics in dealing with the Islamic State (ISIS) and other terrorists: Detonating a missile above a building to warn civilians of an incoming airstrike and then launching the actual airstrike presumably after the civilians have abandoned the building.

The "knock-off-the-roof" tactic has long been utilised by Israel in shelling of Hamas locations and operatives in the Gaza Strip to reduce civilian casualties in urban warfare, CBN News reports.

Other manoeuvres the Israel Defense Forces (IDF) employs include dropping of leaflets, sending SMS messages and placing calls to alert innocent civilians of an impending attack in the area, the report adds.

Air Force Maj. Gen. Peter Gersten, deputy commander for operations and intelligence for the anti-ISIS Operation Inherent Resolve, disclosed this week that Israel's battlefield strategy had been used earlier this month on an alleged ISIS "finance emir" in Mosul, Iraq, who was targeted for assassination.

"The U.S. military had been monitoring his daily routine. He was the major distributor of funds to ISIS fighters," according to Gersten.

"We watched him come and go from his house; we watched his supplies; we watched the security that was involved in it; and we also watched occasionally a female and her children [go] in and out of the quarters," he added.

The U.S. army then began to formulate a plan to get women, children and other civilians out of the building, according to CBN News.

"We went as far as actually to put a Hellfire on top of the building and air-burst it so it wouldn't destroy the building, simply knock on the roof to ensure that she and the children were out of the building ... And then we proceeded with our operations," the official said.

Gersten reportedly acknowledged the Israeli influence, saying, "That's exactly where we took the tactics and technique and procedure from."

He said the U.S. army has "watched and observed" IDF's procedure during past attacks.

Human rights groups like Amnesty International previously slammed Israel's battlefield tactic, claiming that it is not an effective warning strategy.

"There is no way that firing a missile at a civilian home can constitute an effective 'warning,'" said Philip Luther, Middle East and North Africa Director at Amnesty International, about the Israeli practice in 2014, reports CNN.

"Amnesty International has documented cases of civilians killed or injured by such missiles in previous Israeli military operations on the Gaza Strip."

Mahmoud Abu Rahma of the Al Mezan Center for Human Rights, also said that any missile warning cannot be taken lightly and therefore can be dangerous to civilians.

"The sending of a missile cannot be considered a warning. It is the targeting of civilians with a weapon, regardless of how small, and it is a violation of the Geneva conventions," he said

In its 2015 report that discussed the military tactic, the U.N. said: "In a number of incidents examined, the concerned persons either did not understand that their house had been the subject of a 'roof-knock,' or the time given for evacuation between the warning and the actual strike was insufficient."

The report pointed to an incident in which several children died after being given just a few minutes to evacuate at a time when most were sleeping, says CNN.

"'Roof knocks' cannot be considered an effective warning given the confusion they often cause to building residents and the short time allowed to evacuate before the actual strike," the U.N. said.