WASHINGTON – Taking a cue from voters who elected a president promising a different approach, the Obama administration is replacing the general overseeing the war in Afghanistan with a commander who has special-forces experience.

Lt. Gen. Stanley McChrystal, a senior administrator with the Joint Chiefs of Staff, will take the place of Gen. David McKiernan once he is confirmed by the Senate. Lt. Gen. David M. Rodriguez will become McChrystal's deputy with the Senate's approval, which Defense Secretary Robert Gates asked be granted as soon as possible.

"Today we have a new policy set by our new president. We have a new strategy, a new mission and a new ambassador," Gates said Monday at a news conference. "I believe that new military leadership also is needed."

McKiernan's exit after less than a year comes as more than 21,000 additional U.S. forces begin to arrive in Afghanistan, dispatched by President Barack Obama to confront the Taliban more forcefully this spring and summer.

Despite seven years of effort by the U.S. and allies, Afghanistan remains a battleground with an unstable government, a flourishing opium trade and suicide attacks by supporters of al-Qaida.

Obama approved 17,000 additional combat forces for Afghanistan this year, plus 4,000 trainers and other noncombat troops. By year's end, the United States will have more than 68,000 troops in the sprawling country — about double the total at the end of George W. Bush's presidency but still far fewer than the 130,000 still in Iraq.

McKiernan and other U.S. commanders have said resources they need in Afghanistan are tied up in Iraq.

McKiernan issued a short statement saying his time in Afghanistan made him proud to be an American soldier.

"All of us, in any future capacity, must remain committed to the great people of Afghanistan," he said.

Monday's announcement came a week after Afghan civilians were killed during a battle between militants and U.S. forces.

Afghan officials say up to 147 people may have died in the battle in Farah, though the U.S. says that number is exaggerated.

The U.S. on Saturday blamed Taliban militants for causing the deaths by using villagers as human shields in hopes they would be killed. A preliminary U.S. report did not say how many people died in the battle.

Gates visited Afghanistan last week to see firsthand what preparations and plans were under way to set the president's counterinsurgency strategy in motion.

"As I have said many times before, very few of these problems can be solved by military means alone," Gates said Monday. "And yet, from the military perspective, we can and must do better."

He indicated that the Afghan campaign had long lacked the people and money needed due to the Bush administration's focus since 2003 on the Iraq war.

"But I believe, resources or no, that our mission there requires new thinking and new approaches from our military leaders," Gates said.