Doctors Without Borders is calling for the U.S. airstrike on a hospital in Afghanistan on Saturday to be declared a war crime. In order to properly investigate whether or not the U.S. government violated humanitarian law, the organization has made an unprecedented move and requested the help of a never-before-used international fact-finding commision.

This week, President Barack Obama expressed apologies and condolences to the international humanitarian group, also known as Médecins Sans Frontières (MSF), after a U.S. airstrike on the group’s hospital in Kunduz, Afghanistan killed 12 staff members and 10 patients (three children), and left 37 injured. The airstrike is among the worst cases of civilian death inflicted by U.S. forces during their 14 years in Afghanistan, The Guardian reported. However, Dr. Joanne Liu, president of Doctors Without Borders is seeking more than an apology and has called the action a direct “attack on the Geneva Convention,” according to CNN. The group has invited an international commission, known as the International Humanitarian Fact-Finding Commision (IHFFC), to investigate the crime, marking the very first time the commission has been called upon since it was established in 1991.

"Governments up to now have been too polite or afraid to set a precedent," Dr. Joanne Liu, president of Doctors Without Borders, told CNN on Wednesday. "The tool exists, and it is time it is activated." Liu went on to explain how treating the airstrike as a “nonevent” would be likened to “basically giving a blank check to any countries at war.”

Jason Cone, the U.S. executive director for MSF, who was at the hospital at the time of the attack explained how the attack left patients burning in their beds and killed doctors, nurses, and other staff as they worked. “One of our doctors died on an improvised operating table, an office desk, while his colleagues tried to save his life."

According to its website, the IHFFC is an institution designed to ensure respect for and faithful implementation of international humanitarian law. Seeing as hospitals have a special protected status under international humanitarian law, the U.S.’s actions may be considered a war crime. However, in order for the IHFFC to initiate an inquiry into the action, it requires the consent of parties involved. CNN reported that as of today, neither the U.S. or Afghanistan has recognized the commision.

Additionally, the U.S and Afghanistan have both changed their accounts of what happened several times since it was first brought to light last week. According to Liu, it's for this reason that the attack must be investigated by an outside, unbiased body. While the U.S. has described the attack as a mistake, MSF Switzerland General Director Bruno Jochum explained that because the multiple airstrikes had not hit any surrounding buildings, they were in his opinion, “without doubt,” deliberate.

“We're not talking about the random bomb or the random bullet that basically creates damage in one of our facilities," Jochum said, according to Voice of America. "We're talking about the methodic destruction of the main building of the hospital offering intensive care and trauma care to patients.”

However, U.S. Army General John Campbell, who heads the NATO-led coalition in Afghanistan, denied any claims of a deliberate attack on a hospital, and, as reported by The Guardian, explained that the U.S. army “would never intentionally target a protected medical facility.”