Charity group Doctors Without Borders, also known as Medecins Sans Frontieres, or MSF, has sought an independent investigation into the Kunduz hospital attack by The International Humanitarian Fact-Finding Commission.

The International Humanitarian Fact-Finding Commission has been in existence since 1991 but has not been tasked until now. The job of the commission is to investigate violations of international human rights laws.

"Governments up to now have been too polite or afraid to set a precedent. The tool exists, and it is time it is activated," said Dr. Joanne Liu, president of Doctors Without Borders, according to CNN.

Acknowledging the mistake, Gen. John F. Campbell, told a Senate committee, "To be clear, the decision to provide (airstrikes) was a U.S. decision, made within the U.S. chain of command. The hospital was mistakenly struck. We would never intentionally target a protected medical facility," reported CBS News.

President Barack Obama called up Liu and apologized for the attack. "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. 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," said a statement by the White House, reported CNN.

But Liu is keen on an international investigation. "It is unacceptable that the bombing of a hospital and the killing of staff and patients can be dismissed as collateral damage or brushed aside as a mistake," she said during a news conference in Geneva, reported The New York Times. "This was not just an attack on our hospital. It was an attack on the Geneva Conventions. This cannot be tolerated."

"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, acknowledging Obama's apology while also requesting him to allow the investigation by The International Humanitarian Fact-Finding Commission.