US Defense Secretary Robert Gates said on Monday he had sacked the top commander in Afghanistan to make way for "new thinking" at a pivotal moment in the seven-year-old war.
Gates, explaining his decision to replace General David McKiernan after less than a year on the job as the US and NATO commander, said "that our mission there requires new thinking and new approaches from our military leaders."
He said he had tapped Lieutenant General Stanley McChrystal, a former commander of special operations forces in Iraq and Afghanistan, to replace McKiernan.
"Today, we have a new policy set by our new president. We have a new strategy, a new mission, and a new ambassador," Gates told a news conference. "I believe that new military leadership also is needed."
The change comes as President Barack Obama escalates the war against a spreading Taliban insurgency, approving deployments that will double the size of the US force in Afghanistan to 68,000 by the fall.
Along with the troop build-up, the new commander will inherit growing instability in neighboring Pakistan and a public outcry among Afghans over rising civilian casualties from US air strikes.
As part of the overhaul of the US command, the defense secretary also said he had named his military adviser, Lieutenant General David Rodriguez, to serve under McChrystal in a newly created position. He previously oversaw operations in eastern Afghanistan.
The new approach for the Afghan war places a heavy emphasis on Special Forces, the secretive side of counter-insurgency warfare that McChrystal is steeped in, having served as a top commander over special operations since 2003.
McKiernan has had a more traditional career devoted to conventional warfare, overseeing the US-led ground attack that toppled Iraq's Saddam Hussein in 2003.
"I would simply say that both General McChrystal and General Rodriguez bring a unique skill set in counterinsurgency to these issues," Gates said.
Beyond the need for "fresh eyes," Gates did not offer more details about why he had made the move, but said he had taken the decision after consulting with the president, the top US military officer, Admiral Mike Mullen, and the head of US Central Command, General David Petraeus.
"Nothing went wrong and there was nothing specific," he said.
Gates and Mullen, chairman of the Joint Chiefs of Staff, viewed the decision as a logical step after the White House arrived at a new strategy, a defense official said.
The decision drew immediate support from key US lawmakers, including the top Republicans in the Senate Armed Services Committee and its counterpart in the House of Representatives.
McChrystal and Rodriguez "will form a potent team to lead our efforts in Afghanistan. Both bring extensive experience in implementing successful counterinsurgency campaigns," said Republican Representative John McHugh, the top Republican on the House Armed Services Committee.
A similar reshuffle was carried out in Iraq under the previous administration, with a top commander focused on overall strategy and a deputy overseeing day-to-day operations.
The new commander, McChrystal, would likely be promoted to a four-star rank, officials said. And Gates acknowledged that McKiernan's military career was probably over.
The outgoing commander was not at all a failure but McChrystal was
"by all accounts a superstar" with a record of battlefield successes in Iraq and Afghanistan, said analyst Michael O'Hanlon of the Brookings Institution.
"So Gates is perhaps replacing a good general with a very good one," he wrote on the think tank's website.
McChrystal has been credited with targeted operations that hunted down and killed Abu Musab al-Zarqawi, the leader of Al-Qaeda in Iraq, in 2006 and of devising the still classified tactics used to smash Al-Qaeda and Iranian-backed cells in 2007 and 2008.
But special operators also have been accused of detainee abuses under his command.
The United States has about 45,000 troops in Afghanistan, according to the Pentagon, as US Marines have begun to arrive as part of the build-up.
The Afghan war has dragged on for more than seven years since the Taliban were driven from power in a US-led invasion in 2001, launched weeks after the regime refused to hand over its Al-Qaeda allies for the September 11 attacks.