US Defense Secretary: Killing of Americans in Baghdad horrible

WATCH VIDEO

The defense secretary also replaced the commander of the Afghanistan war.

The job will go to Major General Stanley McChrystal, a senior administrator with the Joint Chiefs of Staff.

Gates says fresh thinking is needed to turn around the war against a resurgent Taliban.

And McChrystal brings to the battle his experience as a commander of special forces.

The Pentagon's decision comes as more than 21-thousand additional US forces begin to arrive in Afghanistan. US President Barack Obama dispatched them in a bid to confront the Taliban more forcefully.

And the Pentagon's announcement also comes a week after an unknown number of Afghan civilians were killed during a battle between US forces and militants.

Editor:Zhang Ning