One month after the U.S. bombing of a Doctors Without Borders/Médecins Sans Frontières (MSF) hospital in Afghanistan killed at least 30 people and wounded dozens more, the Obama administration refuses to submit to an independent inquiry while the aid group charges that the lack of global outcry over the incident has become deafening.

“The silence is embarrassing,” MSF executive director Joanne Liu told the Thomson Reuters Foundation in an interview on Monday. “We have seen an erosion over the years of international humanitarian law. Enough is enough. We cannot keep going like this.”

The medical charity has appealed to 76 governments asking for backing for an impartial investigation to clarify what went wrong at the facility in Kunduz—one of the few emergency trauma centers in northeastern Afghanistan—and to prevent any future such tragedy.

“Yet today, as we mourn the killing of our staff and patients, none of the 76 countries have stepped forward to show their support for an independent investigation by the Humanitarian Commission,” said MSF-USA executive director Jason Cone at a commemoration in New York City’s Union Square on Tuesday. “No state has been willing to stand up for the Geneva Conventions and the laws of war.”

Including—and perhaps most egregiously—the United States.

“That is why we again call on President Barack Obama to give his consent for the United States to participate in an independent investigation by the International Humanitarian Fact­-Finding Commission,” Cone said. “Consenting to such an investigation would send a powerful signal of the U.S. government’s commitment to and respect for international humanitarian law and the rules of war.”

More than 415,000 people have signed onto a petition backing this demand.

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