U.S. military to investigate Mosul airstrike that killed dozens of civilians

The U.S. military has launched a formal investigation into what role the U.S. played in the deaths of dozens of civilians in Mosul, Iraq, earlier this month, amid warnings from a top American general that the dense urban fight is making it harder to avoid killing innocents.

Gen. Joseph Votel, head of U.S. Central Command, told Congress that Islamic State militants are exploiting American sensitivities to civilian casualties, using people as human shields to avoid being targeted by strikes.

"As we move into the urban environment it is going to become more and more difficult to apply extraordinarily high standards for things we are doing, although we will try," Votel said during a House Armed Services meeting.

Republican Rep. Martha McSally of Arizona, a retired Air Force colonel, questioned whether the high standards are "ridiculous," because they allow militants to use civilians as a defence against airstrikes so they can "live to fight another day." The result, she said, is just more innocent deaths.

Votel said the investigation will look at what Islamic State militants did to contribute to the civilian deaths in the March 17 strike. He and others have said the munitions used by the U.S. that day should not have taken the entire building down, suggesting that militants may have deliberately gathered civilians there and planted other explosives.

He said U.S. investigators have visited the site and that the review is looking at 700 weapons system videos over a 10-day period to help understand the effects of the munitions used. They also will review intelligence provided by the Iraqi forces.

Senior U.S. military officials said they have now seen several instances where ISIS militants have gathered a large number of people and held them captive in a building, and then put a sniper on the roof to fire at U.S. or allied forces in an effort to draw an attack on the building, and possibly kill dozens of innocent civilians. The relatively new tactic has been used in the West Mosul fight, said the officials, who were not authorized to discuss the military operations publicly so spoke on condition of anonymity.

Coalition needs to take precautions: Amnesty

In one instance, the officials said a precision U.S. strike took out the sniper but left the building intact. Later, they said, civilians were seen being freed from the building. The officials said the U.S., as a result, has to carefully calculate what types of munitions to use in order to limit destruction. At times the military will decide to wait rather than execute an immediate strike.

They noted, however, that if U.S. or partner forces are being attacked, the U.S. will launch strikes to defend them. And that decision can be made quickly by commanders on the ground, closer to the fight.

Votel also told the committee that nearly 800 Iraqi security forces have been killed and 4,600 wounded in the increasingly brutal battle to retake Mosul from ISIS extremists that began last fall.

Under questioning from lawmakers, Votel repeated U.S. military assertions that the military rules of engagement have not been changed or relaxed to allow for more civilian casualties. He said the only change authorized late last year was to allow certain combat decisions be made by U.S. commanders closer to the fight as the battle moved into the densely populated areas of the city. That decision removes a layer of approval that was previously needed, but still requires the commander on the ground to go through the same analysis and consideration of civilian casualties that has been done all along.

The senior military officials said that before the decision-making was streamlined, there were almost daily instances when the delay in getting approval for a strike allowed a target to get away.

Votel and other military officials have, in recent days, acknowledged that the U.S. probably played a role in the civilian casualties. Residents and outside groups have said the explosion killed at least 100 people.

Amnesty International on Tuesday said the rising death toll suggested the U.S.-led coalition wasn't taking adequate precautions as it helps Iraqi forces try to retake the city.

The fight for western Mosul began in February after Iraqi security forces pushed ISIS out of the eastern side of the Tigris River city. In recent weeks, ISIS defenders have packed into neighbourhoods with narrow streets and trapped civilians.

Lt. Gen. Stephen Townsend, the top U.S. commander of American forces in Iraq, said Tuesday that the increase in civilian casualties has been "fairly predictable" given the heavily populated urban neighbourhoods. He said the battle in the western portion of the city will be the toughest phase of the war, adding, "it is there that the enemy has invested two-and-a-half years of defensive preparations."