Update 5:10 a.m. EDT: International medical charity Doctors Without Borders announced Sunday that it has pulled out of the Afghan city of Kunduz, after its hospital there was bombed, in what may have been a U.S. air strike.

Kate Stegeman, the group's communications manager, told the Associated Press some staff are working in other health facilities in the city, where troops have been battling Taliban insurgents.

"All critical patients have been referred to other health facilities and no MSF staff are working in our hospital," she said, using the French acronym for the organization.

Original post:

Air strikes on a Doctors Without Borders hospital in the Afghan city of Kunduz, which left 19 people dead and scores wounded were “inexcusable and possibly even criminal,” according to the United Nations' human rights chief.

High Commissioner Zeid Ra'ad Al Hussein called for a full and transparent investigation of the bombing and added, "if established as deliberate in a court of law, an air strike on a hospital may amount to a war crime".

The U.S. military has said it is investigating the incident, which took place in the early hours of Saturday, as U.S. and Afghan forces struggled to oust Taliban militants from Kunduz, which the group seized on Monday.

The military has said that it carried out an air strike "in the vicinity" of the hospital as it targeted Taliban insurgents who were directly firing on U.S. military personnel, Reuters reported.

Doctors Without Borders said in a statement: “All indications currently point to the bombing being carried out by international Coalition forces.”

The White House issued a statement from President Obama, in which he expressed his “deepest condolences,” to those killed and injured in the incident. It added the the U.S. Department of Defense had launched an investigation and the White House would wait for its results before making a definitive judgment on the incident.

Doctors Without Borders had angrily reacted to news of the bombing on Saturday, saying that they had repeatedly informed all parties to the conflict of the hospital's location, and that “sustained bombing,” of the facility continued for 30 minutes after the organization notified U.S. and Afghan military officials that a medical facility was being struck.

During the strikes, the hospital was repeatedly hit during each raid, while surrounding buildings were left mostly untouched, according to a BBC report.

"The bombs hit and then we heard the plane circle round," Heman Nagarathnam, Doctors Without Borders' head of programs in northern Afghanistan, told the agency.

"There was a pause, and then more bombs hit. This happened again and again. When I made it out from the office, the main hospital building was engulfed in flames. Those people that could had moved quickly to the building's two bunkers to seek safety," he added.

The MSF hospital is seen as a key medical lifeline in Kunduz, and its trauma center is the only medical facility in the region that can deal with major injuries. After the bombing, its operations have "effectively stopped," a Doctors Without Borders official told Al Jazeera.