The UN human rights chief says the deadly US airstrike on a hospital in the Afghan city of Kunduz "may amount to a war crime."  

Zeid Ra'ad al-Hussein said on Saturday that the attack on the medical center run by Medecins Sans Frontieres was "utterly tragic, inexcusable, and possibly even criminal."

"This deeply shocking event should be promptly, thoroughly and independently investigated and the results should be made public," Zeid Ra'ad al-Hussein said in a statement.

"The seriousness of the incident is underlined by the fact that, if established as deliberate in a court of law, an airstrike on a hospital may amount to a war crime."

According to the MSF, the airstrike that killed 19 people lasted for more than half an hour after Washington was informed and that both Afghan and US officials were given the precise location of MSF facilities.

Meanwhile, NATO said US forces may have conducted the airstrike, without commenting on the MSF’s comments.

MSF, meanwhile, has held the US-led forces accountable for the attack. "All indications currently point to the bombing being carried out by international Coalition forces," MSF said in a statement.

Zeid further stressed that international and Afghan military planners must respect and protect the lives of civilians at all times, and medical facilities and personnel are “the object of a special protection.”

The MSF trauma center in Kunduz has been working “beyond capacity” over the past several days of clashes in the city, where the Taliban militants overran late last month.

Kunduz police spokesman, Sayed Sarwar Hussaini, has said that Taliban militants had entered the facility and were using it as a firing position.

However, two hospital workers, an aide who was wounded in the bombing and a nurse who was not injured, said that there had been no active clashes nearby and no Taliban militants in the hospital.

US reaction

US Defense Secretary Ashton Carter, meanwhile, has said that Washington has launched a "full investigation" into the “tragic incident.”

Carter added that “US forces in support of Afghan Security Forces were operating nearby, as were Taliban fighters.”

Kunduz has been witnessing heavy clashes between Afghan government forces and Taliban militants. At least 60 people have reportedly been killed and 400 injured over the past few days of fighting.

Human Rights Watch censures the assault

Also criticizing the fatal attack, Human Rights Watch said even if the Taliban had been firing from the medical center, "given the hospital’s protected status and the large numbers of civilians and medical personnel in the facility, attacking the hospital would still likely have been an unlawfully disproportionate attack, causing greater harm to civilians and civilian structures than any immediate military gain."

“The failure of US forces to stop an attack striking a hospital strongly suggests the forces may have violated the laws of war in identifying risks to civilians and civilian objects and in the weapons used or conduct of the military operation,” the rights group said.