Washington, December 10 (RHC)-- The international humanitarian organization Doctors Without Borders -- Médecins Sans Frontières (MSF) -- has repeated calls for an "independent international investigation" into a deadly attack against a hospital in the Afghan northern city of Kunduz.

Doctors Without Borders delivered a petition, signed by more than 548,000 people, to the White House on Wednesday, asking U.S. President Barrack Obama "to consent to an independent investigation."

A U.S. gunship repeatedly bombed the hospital in the early morning hours of October 3rd, killing 22 people, and injuring more than three dozen others. The subsequent destruction of the hospital left several hundred thousand people without access to emergency trauma care, according to the charity organization.

"Attacking a protected site such as a hospital is a grave violation of International Humanitarian Law and the Geneva Conventions. The precise GPS coordinates of the four-year-old MSF hospital in Kunduz were provided to U.S. and Afghan authorities in Washington and Kabul in the days prior to the bombing, and the hospital contained nearly 200 patients and staff at the time of the attack," read the petition.

It also referred to probes by the U.S., NATO, and the Afghan government already under way, noting that "it is impossible to expect the parties involved in the conflict to carry out independent and impartial investigations of acts in which they themselves are implicated."

U.S. Defense Department spokesman Christopher Sherwood told The Independent that he is "aware of" the petition but "can't provide any comment to their wanting the independent investigation." He said: "We take our responsibility to investigate this incident very seriously, and the U.S. team of investigators has gone to great lengths to ensure this investigation provides a full and impartial accounting of the facts and circumstances of this incident."

Following a Pentagon report on the incident, U.S. Army General John Campbell, the commander of international forces in Afghanistan, said the tragic event was "an example of human and process error."

"The headquarters was aware of the coordinates for the MSF trauma center and had access to the no-strike list but did not realize that the grid coordinates for the target matched a location on the no-strike list or that the aircrew was preparing to fire on a hospital."