The Paris-based medical charity (MSF) held a rally and moment of silence Tuesday in New York City's Union Square.

Carrying signs that read, "Even war has rules," demonstrators repeated the organization's demand for an independent investigation into the October 3 air strikes that devastated a trauma center in Kunduz.

New York rally demands answers

"We knowingly take the risks associated with working in war zones," said Jason Cone, executive director of the charity's US branch. "But what happened in Kunduz, the precise targeting, the prolonged destruction of a fully functioning hospital full of patients and health workers, transcended even the bounds of war."

Three separate investigations - led by the US, NATO and the Afghan government - are looking into the strike that killed 30 people. But the charity wants an independent probe by an international fact-finding commission, based in Bern, Switzerland.

One month anniversary

US President Barack Obama has apologized and called the strike a mistake, but the Pentagon has offered varied accounts on why the hospital was apparently targeted by an AC-130 gunship - despite hospital staff supplying military officials with the facility's precise coordinates and pleading with military officials to call off the sustained bombardment during the attack.

The Associated Press has reported that US intelligence was probing whether Taliban fighters had been based in the hospital. But MSF officials deny that there was any Taliban present in the complex.

The head of the charity's Swiss branch, Thomas Nierle, told the AFP news agency that he had little hope the government probes would provide accountability.

"I think it's a complete illusion to think there will be some sort of justice," he said.

The attack forced the closure of the trauma center in Kunduz, the only one of its kind in the war-torn region.

jar/jr (AP, AFP)