Kabul, October 15 (RHC)-- Two more staff members of Doctors Without Borders, also known by its French name, Medecins Sans Frontieres (MSF), are believed to have been killed in the recent U.S. airstrike on its hospital in northern Afghanistan, raising the death toll to 24.

The MSF announced the new tally on Wednesday with a spokeswoman saying that 22 other staff who had gone missing are now accounted for. The deadly airstrike on October 3rd, which lasted for “more than an hour,” according the MSF chief, led to the closure of the MSF-run trauma hospital in the city of Kunduz, depriving tens of thousands of Afghans of health care.

The spokeswoman, whose name was not mentioned in the report, added that nine patients are still missing and the MSF continues the search for them. Taking responsibility for the airstrike, Washington called it "a mistake" -- while President Barack Obama was forced to apologize to the MSF under mounting pressure from international aid groups.

The MSF has asked the Berne-based International Humanitarian Fact-Finding Commission (IHFFC) to investigate the deadly strike, and the IHFFC has contacted the U.S. and Afghan governments to get their green light for launching the probe.

“We have received apologies and condolences, but this is not enough. We are still in the dark about why a well-known hospital full of patients and medical staff was repeatedly bombarded for more than an hour,” said Joanne Liu, the president of MSF International.

According to the MSF, the commission is to collect facts and evidence from the US, NATO and Afghanistan, and testimony from the MSF staff and patients who survived the attack for the investigation.

Kunduz witnessed heavy clashes between Afghan government forces and Taliban militants after the latter stormed the city on September 28 and held it for three days before being driven back.