Members of the civil defense search for bodies in the rubble of a building in the Mosul al Jadidah neighborhood of Mosul. (Alice Martins for The Washington Post)

Even though Iraqi civil defense workers are still sorting through the rubble, the March 17 U.S. airstrike in West Mosul, if confirmed, could potentially rank among one of the most devastating attacks on civilians by American forces in more than two decades.

Residents from the neighborhood where the strike occurred said that 137 civilians were killed, while Iraqi officials have said that upward of 80 people had been pulled from the rubble. Chris Woods, the director of the monitoring group Airwars.org, said the range of dead have been reported from 101 to 511, though the likely numbers are somewhere between 130 and 230.

On Monday, Col. John Thomas, the spokesman for the U.S. command that oversees the wars in Iraq and Syria, said that the U.S. military was investigating the March 17 bombing in addition to a number of other strikes that happened during the same time in roughly the same area.

In a statement U.S. Central Command said it had received multiple "conflicting allegations" placing a strike in the area sometime between March 17 and 23. (Loveday Morris/The Washington Post)

The battle for West Mosul, which began earlier this year, has been marked by heavy fighting in dense urban terrain. Islamic State fighters have used residents as human shields around their defensive positions and relied heavily on booby traps, roadside bombs and suicide vehicles to delay the U.S.-backed Iraqi advance. Even before Iraqi forces moved into the western part of Mosul, there were multiple allegations of civilian casualties during the four months it took to take the eastern side of the city.

When asked about the loss of civilian life Monday, Secretary of Defense Jim Mattis told reporters that the U.S.-led coalition goes out of its way “to always do everything humanly possible to reduce the loss of life or injury among innocent people. The same cannot be said for our adversaries.”

There have been numerous U.S. air attacks that have killed dozens since the Gulf War. These include two potential strikes in Syria just this month, the 2015 Kunduz Hospital strike in Afghanistan, and roughly a dozen errant wedding party strikes in Iraq, Afghanistan and Yemen over the years. Yet there are only a handful of U.S.-aerial bombardments that have killed more than a hundred civilians in a single event.

Some of these strikes below:

Kunduz Province, Afghanistan. Sept. 4 2009.

At the direction of German ground forces, U.S. F-15 multi-role fighters bombed a column of suspected Taliban tanker trucks, killing anywhere between 91 and 172 civilians. Fearing an attack from the aircraft, the Taliban had abandoned the trucks in a river bed before the bombs struck. Instead of striking a large number of Taliban fighters, U.S. aircraft targeted locals that were siphoning off gas from the trucks. According to a 2010 report in the German publication Spiegel, the German army identified 102 families that would receive condolence payments for the strikes — 91 killed and 11 seriously injured. A German-based lawyer for the victims maintained that 179 had been killed.

Farah Province, Afghanistan. May 4, 2009

After a firefight with Afghan soldiers, policemen and American troops, a group of Taliban retreated into the village of Granai. The U.S. forces called for air support, and soon after, a combination of fighters and bombers, including what was believed to be a B-1 strategic bomber, dropped thousands of pounds of bombs on the village killing an estimated 140. According to a Reuters article from time, the Afghan investigation into the strike found that of the 140 victims, 93 were children and only 22 were adult males. Pentagon estimates put the civilian dead at a much lower, saying the majority of those killed were insurgents. The U.S. attack on Granai forced Gen. Stanley McChrystal — then the commander of U.S. forces in Afghanistan — to heavily restrict the criteria for airstrikes in Afghanistan. That criteria — decried by many ground troops and commanders — has served as the basis for the current rules of engagement in Iraq, Syria and Afghanistan.

Baghdad. Feb. 13, 1991.

The attack on the Amiriyah air-raid shelter during the Gulf War by U.S. stealth aircraft resulted in the loss of anywhere between 200 and 300 civilians, according to a Human Rights Watch report from 1991. Later news reports said that more than 400 had been killed. The shelter was packed with civilians when bunker busting bombs penetrated the roof at around 5 a.m. According to the report, the Pentagon said it had intercepted military communications from the building and that military personnel were stationed near it. The U.S. military, however, also knew the building had been used as a shelter during the Iran-Iraq war. Lawyers in Belgium accused former president George H.W. Bush; Richard B. Cheney, who was Defense secretary at the time, and Colin Powell of war crimes because of Amiriyah strike, but in 2003 the country’s highest court dismissed the complaints.

Around the same time, in February 1991, British bombers struck multiple bridges in southern and western Iraq, killing more than 100 in each attack, according to local reports at the time.

The contrast is stark between the loss of life from the 1991 bombing campaign at the outset of the Gulf War and the opening salvos of Operation Iraq Freedom in 2003. A month-long Human Rights Watch investigation following the invasion found that “in most cases, aerial bombardment resulted in minimal adverse effects to the civilian population.”

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