Obama apologizes for Afghan airstrike

President Obama called the head of Doctors Without Borders on Wednesday to apologize for a U.S. airstrike that killed 12 aid workers in Afghanistan, as the relief group stepped up its calls for an independent inquiry into an attack it has labeled a possible war crime.

White House press secretary Josh Earnest said Obama spoke with Doctors Without Borders president Joanne Liu and expressed his condolences for the strike against a hospital in northern Afghanistan.

"When we make a mistake, we are honest, own up to it and apologize," Earnest told reporters at the White House. "The Department of Defense goes to great lengths to prevent civilian casualties, but in this case, there was a mistake, and it's one that the United States owns up to."

At least 22 people, including the 12 Doctors Without Borders staff, were killed early Saturday when a U.S. AC-130 gunship launched repeated attacks on the facility in the city of Kunduz, where Afghan forces are battling to oust Taliban fighters who overran the city a week ago.

Earnest said Obama promised a transparent and thorough investigation "and if necessary will implement changes to make sure tragedies like this one are less likely in the future." Obama also spoke by phone with Afghan President Ashraf Ghani to express condolences for the "loss of life" and to "commend the bravery of the Afghan national forces."

Earnest declined to say whether the White House would support demands from the aid group, also known as Medecins Sans Frontieres, or MSF, for an independent probe of the incident. The Pentagon, NATO, and the Afghan government are conducting their own investigations into the attack.

Speaking to reporters in Geneva earlier in the day, Liu said the proposed commission would gather evidence from the United States, NATO and Afghanistan. After that, the charity would decide whether to seek criminal charges for loss of life and damage.

"If we let this go, we are basically giving a blank check to any countries at war," she said.