WASHINGTON, April 29 (Xinhua) -- A medical charity whose hospital in Afghanistan was bombed by U.S. forces last year said on Friday that the U.S. military operation failed to follow the basic laws of war.

Earlier in the day, the Pentagon claimed its airstrike on the trauma hospital, operated by the Doctors Without Borders (MSF), was not a war crime because it was unintentional.

The airstrike on the hospital in Afghanistan city of Kunduz on Oct. 3, 2015 killed 42 people, including 14 MSF staff members, and wounded dozens more, causing a world-wide wave of outrage and criticism against the White House and Petagon.

"Today's (Pentagon) briefing amounts to an admission of an uncontrolled military operation in a densely populated urban area, during which U.S. forces failed to follow the basic laws of war," said Meinie Nicolai, MSF President.

"The threshold that must be crossed for this deadly incident to amount to a grave breach of international humanitarian law is not whether it was intentional or not," Nicolai said in a statement sent to Xinhua.

"Whether in Afghanistan, Syria, or Yemen, armed groups cannot escape their responsibilities on the battlefield simply by ruling out the intent to attack a protected structure such as a hospital," the statement stressed.

Nicolai said MSF will take time to examine the Pentagon probe report but "it cannot be satisfied solely with a military investigation into the Kunduz attack."

MSF has condemned the airstrike as a war crime and repeatedly called for an independent and impartial investigation into the attack. But that "has so far gone unanswered," Nicolai noted.

Instead, the Pentagon conducted a military probe which found no armed combatants within and no fire from the hospital compound, claiming the U.S. forces mistook the hospital for another compound that was serving as a Taliban headquarters.

General Joseph Votel, the head of U.S. Central Command,told reporters at the Pentagon earlier Friday that the attack "resulted from a combination of human errors, process errors and equipment failures".

He said about 16 military personnel, including a general officer, were disciplined for their role in the airstrike. However, none of them will face criminal charges.