Profile: Gen Stanley McChrystal

"Getting fresh thinking, fresh eyes on the problem."

That is the reason US Defence Secretary Robert Gates gave in May for removing Gen David McKiernan as the US military's commander in Afghanistan and replacing him with Gen Stanley McChrystal.

Gen McChrystal, with his special forces background, represents the future of warfare as envisaged by Mr Gates and President Barack Obama - away from conventional military planning, towards modern, asymmetric warfare.

One of his first acts upon taking up the new post in June was to make clear to US and Nato forces that they were to move away from the idea that they were fighting an all-out war against the Taliban and its allies, and instead focus on protecting Afghanistan's civilians.

This included halting indiscriminate air strikes, which have killed large numbers of civilians, and getting more troops out on patrol.

Then in a bleak assessment sent to the White House in August, Gen McChrystal warned that his mission might fail within 12 months if he was not given extra troops and the training of the Afghan security forces was not speeded up. He also censured the Afghan government.

"Failure to gain the initiative and reverse insurgent momentum in the near-term... risks an outcome where defeating the insurgency is no longer possible," he wrote. "Additional resources are required."

Hunting al-Zarqawi

Born in 1954 into a military family, Gen McChrystal graduated from the US military academy at West Point in 1976 and spent the next three decades ascending through conventional and Special Operations command positions, which included serving during the Gulf War.

"We'll win it when we connect with enough of the Afghan people, when they have finally said: 'Enough'"

In September 2003, he became commanding general of the Joint Special Operations Command (JSOC), a secretive body responsible for the planning and execution of US military special forces missions abroad. In February 2006, he was promoted to overall commander.

Few details are known, but under his command JSOC forces captured the former Iraqi president, Saddam Hussein, and killed the leader of al-Qaeda in Iraq, Abu Musab al-Zarqawi.

He is also said to have built close relationships with other military and intelligence organisations, such as the CIA, which JSOC had traditionally avoided.

Gen McChrystal's reputation was somewhat tarnished in 2007, however, when a Pentagon investigation into the accidental killing three years earlier of Cpl Pat Tillman, a former NFL football star, in Afghanistan by fellow Army Rangers held him accountable for providing inaccurate information when recommending him for a medal.

The general had wrongly suggested in a citation that Cpl Tillman had been killed by enemy fire, the investigation found, but the army declined to punish him.

The previous year had also seen a JSOC unit called Task Force 6-26, which led the hunt for Zarqawi and many of whose members were under his command, accused of abusing detainees in Iraq.

'Serious situation'

In 2008, Gen McChrystal became director of the Joint Staff, working for the chairman of the joint chiefs of staff, Adm Mike Mullen.

Adm Mullen recommended him to Mr Gates as a possible replacement for Gen McKiernan earlier this year, when President Obama is said to have become sceptical about his suitability for Afghanistan.

Gen McKiernan rose to prominence in 2003 as the leader of all coalition forces during the US-led invasion of Iraq, and correspondents say the White House believed Gen McChrystal's special operations tactics were more likely to be successful combating the resurgent Taliban.

In an interview with the BBC in August, Gen McChrystal described his approach.

"The situation is serious, and we need to turn the momentum of the enemy. We can do that," he said.

"What we need to do is to correct some of the ways we operated in the past. We need show the kind of resolve and the imagination in some cases to do this smarter and to do it right."

"We'll win it when we connect with enough of the Afghan people, when they have finally said: 'Enough,'" he added.