(CNN) President Barack Obama has personally apologized. But he didn't go far enough, according to Doctors Without Borders, the aid group whose hospital in the Afghan city of Kunduz was hit by a deadly U.S. airstrike. 
 
 The charity group -- which is also known as Medecins Sans Frontieres, or MSF, and provides medical care in some of the world's most dangerous places -- is calling the strike an "attack on the Geneva Conventions" and urging an independent investigation by a never-before-used international commission. 
 
 The International Humanitarian Fact-Finding Commission has been in existence since 1991. It requires a request by one of the 76 nations that have signed on to it for it to begin its work. Its job is to investigate whether international humanitarian law has been violated. 
 
 "Governments up to now have been too polite or afraid to set a precedent," Dr. Joanne Liu, president of Doctors Without Borders, said Wednesday. "The tool exists, and it is time it is activated." 
 
 On Wednesday morning, Obama called and apologized directly to Liu. In a White House statement on that conversation, he highlighted a U.S. military investigation into the strike and pledged full support to a joint NATO and Afghan government probe. 
 
 But there was no mention of the International Humanitarian Fact-Finding Commission. 
 
 "President Obama expressed regret over the tragic incident and offered his thoughts and prayers on behalf of the American people to the victims, their families, and loved ones," the White House statement said. 
 
 "Acknowledging the great respect he has for the important and lifesaving work that MSF does for vulnerable communities in Afghanistan and around the world, the President assured Liu of his expectation that the Department of Defense investigation currently underway would provide a transparent, thorough and objective accounting of the facts and circumstances of the incident." 
 
 The Doctors Without Borders chief acknowledged Obama's apology, but doesn't want him to stop there. She pushed for the United States to allow an international investigation. 
 
 "We reiterate our (request) that the U.S. government consent to an independent investigation led by the International Humanitarian Fact-Finding Commission to establish what happened in Kunduz, how it happened, and why it happened," Liu said. 
 
 For charity, 'the biggest loss of life ... in an airstrike' 
 
 The attack in the embattled city Saturday killed 12 medical staff members and at least 10 patients, three of them children. It was "the biggest loss of life for our organization in an airstrike," Liu said. 
 
 'If we let this go, we are basically giving blank check to any countries at war' says #MSF Int'l Prez @JoanneLiu_MSF pic.twitter.com/p3YDpUepbq — MSF East Africa (@MSFNairobi) October 7, 2015 
 
 Another 37 people were wounded, according to the global charity group, which works in conflict zones to help victims of war and other tragedies. 
 
 Gen. John Campbell, commander of U.S. forces in Afghanistan, has said the hospital was hit accidentally during an American airstrike. The Pentagon is carrying out an investigation, as are NATO and Afghanistan. 
 
 "If errors were committed, we will acknowledge them," Campbell said. "We will hold those responsible accountable, and we will take steps to ensure mistakes are not repeated." 
 
 Doctors Without Borders said it wants a full and transparent investigation by an independent agency. 
 
 "Their description of the attack keeps changing -- from collateral damage, to a tragic incident, to now attempting to pass responsibility to the Afghanistan government," the group said. 
 
 What the U.S. said and when Saturday, 3 October -- Col. Brian Tribus, spokesman for U.S. Forces in Afghanistan "U.S. forces conducted an airstrike in Kunduz city at 2:15am (local), Oct 3, against individuals threatening the force. The strike may have resulted in collateral damage to a nearby medical facility. This incident is under investigation." Sunday, 4 October -- Gen. John Campbell, U.S. military chief in Afghanistan "U.S. forces conducted an airstrike in Kunduz city at 2:15am (local), Oct 3, against insurgents who were directly firing upon U.S. service members advising and assisting Afghan Security Forces in the city of Kunduz. The strike was conducted in the vicinity of a Doctors Without Borders medical facility." Monday, 5 October -- Gen. John Campbell, U.S. military chief in Afghanistan "We have now learned that on October 3, Afghan forces advised that they were taking fire from enemy positions and asked for air support from U.S. forces. An airstrike was then called to eliminate the Taliban threat and several civilians were accidentally struck. This is different from the initial reports, which indicated that U.S. forces were threatened and that the airstrike was called on their behalf." Tuesday, 6 October -- Gen. John Campbell to the Senate committee "On Saturday morning our forces provided close air support to Afghan forces at their request. To be clear the decision to provide aerial fires was a U.S. decision, made within the U.S. chain of command. A hospital was mistakenly struck. We would never intentionally target a protected medical facility ... I assure you that the investigation will be thorough, objective and transparent." 
 
 'Today, we say, 'Enough'' 
 
 The United States has changed its account of what brought on the airstrike. 
 
 First, U.S. officials said that initial reports indicated the airstrike was called to protect U.S. forces. Then it said Afghan forces called for the air support because the Afghans were taking fire. 
 
 "Today, we say, 'Enough,' " Liu said. 
 
 "Today we are fighting back for the respect of the Geneva Conventions. As doctors, we are fighting back for the sake of our patients." 
 
 It's an open question as to whether the International Humanitarian Fact-Finding Commission could initiate an inquiry. The panel's website says it requires the consent of the parties involved, and neither the United States nor Afghanistan recognizes the commission. 
 
 Jason Cone, the U.S. executive director for Doctors Without Borders, called on one of the 76 nations that recognize the panel to press the issue on the charity's behalf, though none of the 76 had stepped forward as of midday Wednesday. He said the changing U.S. accounts of the strikes underscore the need for an independent inquiry. 
 
 Cone paid tribute to the doctors who he said carried on treating the wounded while watching their colleagues die and while the hospital burned. 
 
 "In Kunduz, our patients burned in their beds, our doctors' nurses and other staff were killed as they worked, our colleagues had to operate on each other. One of our doctors died on an improvised operating table, an office desk, while his colleagues tried to save his life," Cone said. 
 
 A balance between humanity and military necessity 
 
 Photos: Doctors Without Borders hospital attacked in Afghanistan Photos: Doctors Without Borders hospital attacked in Afghanistan Flames are visible inside a Doctors Without Borders hospital in Kunduz, Afghanistan, after a U.S. airstrike on Saturday, October 3. At least 30 people died in the attack, the charity said in its internal review of the strike released Thursday, November 5. The commander of U.S. forces in Afghanistan has said the hospital was hit accidentally. Hide Caption 1 of 5 Photos: Doctors Without Borders hospital attacked in Afghanistan Doctors Without Borders said it had emailed the GPS coordinates of its main hospital and administration office building at the Kunduz center before the airstrike. The U.S. commander said airstrikes were called after Afghan troops advised they were "taking fire from enemy positions." 
 
 Hide Caption 2 of 5 Photos: Doctors Without Borders hospital attacked in Afghanistan Doctors Without Borders is asking for an indepedent investigation by the International Humanitarian Fact-Finding Commission. President Barack Obama has apologized to the charity group for the attack. Hide Caption 3 of 5 Photos: Doctors Without Borders hospital attacked in Afghanistan The attacks came as fighting intensified between Afghan government forces -- supported by U.S. air power and military advisers -- and the Taliban, which invaded Kunduz in late September. Hide Caption 4 of 5 Photos: Doctors Without Borders hospital attacked in Afghanistan "We were running a hospital treating patients, including wounded combatants from both sides -- this was not a 'Taliban base,' " said Dr. Joanne Liu, international president of Doctors Without Borders or Médecins Sans Frontières, upon release of the group's internal review of the attack. Hide Caption 5 of 5 
 
 In general terms, a war crime may be committed when there is an attack on a civilian population during an armed conflict, said Steven Kay, a lawyer who defended Kenyan President Uhuru Kenyatta against charges of crimes against humanity at the International Criminal Court, 
 
 There is an extensive body of law that regulates military action during conflict. 
 
 The aim, said Anthony Dworkin, a human rights expert at the European Council on Foreign Relations, is to draw a balance between what armed forces are justified to do out of military necessity -- which includes causing collateral damage to civilians -- and the principles of humanity. 
 
 "Hospitals enjoy a special protected status under international humanitarian law. So, to attack a hospital or medical facility, whether it is a civilian or military installation, is a crime," Kay said. 
 
 Saturday wasn't the first time Doctors Without Borders has complained about military action on the Kunduz hospital. 
 
 In July, the aid group condemned what it called a "violent incursion by armed members of Afghan Special Forces." The troops allegedly entered the hospital -- which, according to MSF, "has a strict no weapons policy" like its other facilities -- and "physically assaulted three MSF staff members (and arrested) three patients." Those patients were released after an hour. 
 
 "Since it opened in 2011, Kunduz Trauma Center has been a place where all patients can receive free medical and surgical care safely," MSF's Director of Operations Dr. Bart Janssens said at the time. "This serious event puts at risk the lives of thousands of people who rely on the center for urgent care." ||||| WASHINGTON/GENEVA U.S. President Barack Obama on Wednesday apologized to Medecins Sans Frontieres for the deadly bombing of its hospital in Kunduz, Afghanistan, while the medical charity pressed its demand for an international commission to investigate what it calls a war crime. 
 
 MSF said that an independent humanitarian commission created under the Geneva Conventions in 1991 should be activated for the first time to handle the inquiry. Three investigations have already begun into Saturday's air strike that killed 22 people, including 12 MSF staff. 
 
 Obama telephoned MSF, or Doctors Without Borders, International President Joanne Liu to apologize and express his condolences, White House spokesman Josh Earnest said. Asked whether Obama offered some explanation to Liu, Earnest said no. 
 
 "He merely offered his heartfelt apology" and a commitment to find out what went wrong, he said. 
 
 Earnest said Obama told Liu that a U.S. investigation would "provide a transparent, thorough and objective accounting of the facts and circumstances of the incident. And that, if necessary, the president would implement changes to make tragedies like this one less likely to occur in the future." 
 
 MSF said that the commission's inquiry would gather facts and evidence from the United States, NATO and Afghanistan, as well as testimony from MSF staff and patients who survived. 
 
 Only then would MSF consider whether to bring criminal charges for loss of life and partial destruction of its trauma hospital, which has left tens of thousands of Afghans without access to health care, it said. 
 
 "If we let this go, as if it was a non-event, we are basically giving a blank check to any countries who are at war," Liu told a news briefing in Geneva. "If we don't safeguard that medical space for us to do our activities, then it is impossible to work in other contexts like Syria, South Sudan, like Yemen." 
 
 Neither the United States nor Afghanistan were signatories to the International Humanitarian Fact-Finding Commission (IHFFC) but Jason Cone, executive director of MSF in the United States, called on Obama to consent to the commission. 
 
 "Doing so will send a powerful signal of the U.S. government's commitment to and respect for international humanitarian law under rules of war," Cone said at a news conference in New York. 
 
 The White House said Obama had also called Afghan President Ashraf Ghani to express his condolences. The United States military took responsibility on Tuesday for the air strike, calling it a mistake. 
 
 Earnest said "there is no evidence that ... I've seen or that anybody else has presented that indicate that this was anything other than a terrible, tragic accident." 
 
 U.S. Defense Secretary Ash Carter, speaking to reporters in Rome on Wednesday, said the investigation would "hold accountable anyone responsible for conduct that was improper." 
 
 HOSPITAL CHAOS 
 
 Liu spoke of the chaos as the bombs fell for an hour. 
 
 "Our patients burned in their beds, MSF doctors nurses, and other staff were killed as they worked. Our colleagues had to operate on each other," she said. 
 
 The Afghan Ministry of Defence said on Sunday Taliban fighters had attacked the hospital and were using the building "as a human shield", which the medical group denied, while pointing out it would be a war crime not to treat the wounded. 
 
 Liu said an impartial commission, which can be set up at the request of a single state under the Geneva Conventions that establish international standards for conducting war, was needed due to "inconsistencies between the U.S. and Afghan accounts". 
 
 The United Nations has condemned the attack but said it would wait for the results of U.S., NATO and Afghan investigations before deciding whether to support an independent probe. 
 
 MSF's hospital in Kunduz had treated nearly 400 people, including some Taliban, wounded in heavy fighting in the days before the attack, MSF's Bruno Jochum said. 
 
 Its GSP coordinates had been shared with all authorities. 
 
 "We had eight ICU (intensive care unit) beds with ventilators, this was high-tech medicine. This was not the little bush hospital. You could not miss it," Liu said. 
 
 "Today we say enough, even war has rules." 
 
 (Additional reporting Steve Scherer in Rome, Doina Chiacu and Lisa Lambert in Washington and Daniel Bases in New York; Editing by David Storey and Grant McCool) ||||| (CNN) The bombing by U.S. forces of a Doctors without Borders hospital in the Afghan city of Kunduz, which left at least 22 people dead, has caused outrage and raised questions around the world. 
 
 The United States says it is conducting a "full investigation," but the medical aid group, also known as Medecins Sans Frontieres, or MSF -- which lost 12 staff members in the attack -- has called for an independent inquiry "under the clear presumption that a war crime has been committed." 
 
 Doctors without Borders is asking for an investigation to be carried out by a never-before-used commission: the International Humanitarian Fact-Finding Commission. 
 
 It's an open question as to whether an inquiry could be initiated, as the commission's website says it requires the consent of the parties involved, and neither the United States, Afghanistan, nor France recognizes the commission. 
 
 CNN asked Steven Kay, who defended Kenyan President Uhuru Kenyatta against charges of crimes against humanity at the International Criminal Court, and Anthony Dworkin, co-editor of "Crimes of War: What the Public Should Know," about the case. 
 
 What constitutes a war crime? 
 
 Photos: Doctors Without Borders hospital attacked in Afghanistan Photos: Doctors Without Borders hospital attacked in Afghanistan Flames are visible inside a Doctors Without Borders hospital in Kunduz, Afghanistan, after a U.S. airstrike on Saturday, October 3. At least 30 people died in the attack, the charity said in its internal review of the strike released Thursday, November 5. The commander of U.S. forces in Afghanistan has said the hospital was hit accidentally. Hide Caption 1 of 5 Photos: Doctors Without Borders hospital attacked in Afghanistan Doctors Without Borders said it had emailed the GPS coordinates of its main hospital and administration office building at the Kunduz center before the airstrike. The U.S. commander said airstrikes were called after Afghan troops advised they were "taking fire from enemy positions." 
 
 Hide Caption 2 of 5 Photos: Doctors Without Borders hospital attacked in Afghanistan Doctors Without Borders is asking for an indepedent investigation by the International Humanitarian Fact-Finding Commission. President Barack Obama has apologized to the charity group for the attack. Hide Caption 3 of 5 Photos: Doctors Without Borders hospital attacked in Afghanistan The attacks came as fighting intensified between Afghan government forces -- supported by U.S. air power and military advisers -- and the Taliban, which invaded Kunduz in late September. Hide Caption 4 of 5 Photos: Doctors Without Borders hospital attacked in Afghanistan "We were running a hospital treating patients, including wounded combatants from both sides -- this was not a 'Taliban base,' " said Dr. Joanne Liu, international president of Doctors Without Borders or Médecins Sans Frontières, upon release of the group's internal review of the attack. Hide Caption 5 of 5 
 
 In general terms, a war crime may be committed when there is an attack on a civilian population during an armed conflict, Kay says. 
 
 There is an extensive body of law that regulates military action during conflict. 
 
 The aim, says Dworkin, is to draw a balance between what armed forces are justified to do out of military necessity -- which includes causing collateral damage to civilians -- and the principles of humanity. 
 
 "Hospitals enjoy a special protected status under international humanitarian law. So, to attack a hospital or medical facility, whether it is a civilian or military installation, is a crime," says Kay. 
 
 However, if the hospital is used to support military operations for nonmedical purposes, then it loses its special protection status and it can be attacked by the opposition forces. 
 
 But the law requires that the attack be proportionate to the threat and risk involved. 
 
 Can the hospital bombing be considered a war crime? 
 
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 Doctors without Borders says the hospital was bombed for more than half an hour after it notified NATO and U.S. officials that the facility was under attack. 
 
 In this case, according to Kay, the hospital bombing would be justified, and not considered a war crime, only if there was a clear, imminent or ongoing attack at the hospital. 
 
 Kay notes that there have been instances of medical installations being used as cover for forces to launch attacks. 
 
 Kay cites examples including allegations that during the last three decades of the Sri Lankan civil war, the separatist Tamil Tigers based fighters and used force at protected sites like civil hospitals. A U.N. panel found credible allegations of war crimes committed by both sides during the final stages of the country's civil war. 
 
 Dworkin makes the point that hospitals can be attacked by mistake. 
 
 In comments Monday, Gen. John Campbell, the commander of U.S. forces in Afghanistan, described the hospital deaths as an error, saying "several innocent civilians were accidentally struck" in an operation targeting Taliban fighters. 
 
 Dworkin says he believes that in this case, the United States would not be found guilty of committing a war crime because although armies are forbidden from conducting indiscriminate attacks, "the laws do recognize that mistakes happen in the fog of war." 
 
 But it would come down to a matter of evidence and establishing exactly what happened. 
 
 What proof is required to prosecute a war crime? 
 
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 "Beyond reasonable doubt -- the criminal standard of proof," says Kay. 
 
 He adds that cases like this are generally quite easy because state military operation are often well documented. 
 
 "Satellite photographs, drones ... all this is recorded in live time," he says. "Military operations don't happen in a garden shed. Hundreds of people (are) involved in planning an operation and monitoring, because they are monitoring a plane flying in the sky that is worth $100 million." 
 
 What happens next? 
 
 Armed forces have a duty to investigate the conduct of their own members because if there has been breach of humanitarian law, they have the first responsibility to punish those responsible, says Kay. 
 
 It doesn't automatically escalate to the international level, but there is a duty on the state involved to investigate and discipline, he says. Failure to investigate and discipline adequately would then bring scrutiny at a higher level, he adds. 
 
 Can the U.S. be prosecuted at the ICC for war crimes? 
 
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 The International Criminal Court is the first permanent court established to bring to justice to those who commit the most serious crimes of concern to the international community. 
 
 The ICC prosecutes individuals, not countries, and in theory the person who gives the command can be held responsible for the crime, just as the subordinate who executed the order can be, says Dworkin. 
 
 However, the jurisdiction of the ICC extends only to states that have ratified the treaty that created the court. The United States is not a state party to the ICC treaty, or so-called Rome Statute , its citizens cannot be tried at the International Criminal Court. 
 
 In this particular case, says Dworkin, Afghanistan is a signatory to the ICC, so the court would have jurisdiction over any crimes committed on its territory.
– Doctors Without Borders isn't letting the deadly airstrike on a hospital in Afghanistan slip quietly away. The group Wednesday called the US bombing that killed 12 of its staffers and 10 patients "an attack on the Geneva Conventions" and called for an unprecedented independent investigation, reports Voice of America. "Even war has rules," said its president, Joanne Liu. Her group wants the International Humanitarian Fact-Finding Commission—a panel set up under the Conventions in 1991 but never used—to launch an inquiry. It takes the request of one its 76 signatory nations to launch one, reports CNN. "Governments up to now have been too polite or afraid to set a precedent," said Liu. "The tool exists, and it is time it is activated." The group has called the airstrike a war crime, and Liu says internal investigations by the US or Afghanistan aren't enough. “If we let this go as if it were a nonevent, we are basically giving a blank check to any countries at war." Only when the investigation is complete will the group decide whether to pursue criminal charges, reports Reuters. (On Tuesday, a US general called the airstrike a mistake.)