The deadly US air strike that hit a hospital in Kunduz, Afghanistan was a mistake made within the US military�s chain of command, according to the American commander of NATO forces in Afghanistan.

In a hearing on Tuesday at the Senate Armed Services Committee in Congress, US Army General John Campbell said he has called on his forces to undergo training to review rules of engagement to prevent similar incidents.

He pledged to launch an objective and transparent probe into the hospital bombing.

"To be clear, the decision to provide aerial fires was a US decision made within the US chain of command," Campbell said at the Senate hearing.

Campbell's remarks are the most direct acknowledgement yet by the US Defense Department that the strike on the hospital was carried out by the US military.

On Monday, Campbell only said that US forces had responded to a request for support from Afghan forces.

On Saturday, US forces struck an Afghan hospital run by Doctors Without Borders, or Medecins Sans Frontieres (MSF), an international medical charity group based in Geneva, Switzerland.

The attack killed 12 medical staff members and at least 10 patients, three of them children, and injured at least 37 people, according to the medical aid organization.

Officials at the humanitarian organization have blamed the United States, demanding an independent investigation into the incident and calling it a war crime.

White House spokesman Josh Earnest said on Tuesday that US President Barack Obama expected measures to be taken to prevent such an incident from recurring in the future.

About 9,800 US troops are currently deployed in Afghanistan, most of which provide training and support to Afghan troops as part of NATO�s Resolute Support Mission, which is also led by Campbell.

The US and its allies invaded Afghanistan on October 7, 2001 as part of Washington�s so-called war on terror. The offensive removed the Taliban from power, but after 14 years, the foreign troops have still not been able to establish security in the country.

By Press TV