* Gates asks for Afghanistan commander's resignation
* Pentagon chief says fresh military thinking was needed
* U.S. special operations expert set to replace McKiernan (Recasts)
By David Morgan
WASHINGTON, May 11 (Reuters) - Defense Secretary Robert Gates dismissed the top U.S. and NATO commander in Afghanistan on Monday and picked a former special forces commander to oversee President Barack Obama's strategy against a growing Taliban insurgency.
Gates asked for the resignation of Army General David McKiernan less than a year into a command that normally would last 18 to 24 months.
"This is the right time to make the change," Gates said at the Pentagon after returning from Afghanistan.
Violence in Afghanistan has surged to its highest levels since the 2001 U.S. invasion toppled the Taliban, which had harbored the al Qaeda network responsible for the Sept. 11 attacks on the United States.
Gates recommended Army Lieutenant General Stanley McChrystal, a former Green Beret, to take over the command of the 45,000 U.S. troops and 32,000 forces from other NATO countries now in Afghanistan.
McKiernan had pushed for an additional 10,000 troops in 2010, a proposal that appeared to run afoul of Gates, who has expressed a reluctance to boost the force level beyond 68,000.
"Policymakers for a while had been losing faith in General McKiernan's ability to really understand this conflict," military analyst Andrew Exum of the Center for a New American Security, a Washington think tank. He described a shift from McKiernan's terrain- and enemy-focused strategy to a population-centered battle plan.
The Obama plan for Afghanistan calls for a military push to reverse deteriorating security, a surge of civilian aid and development assistance and possible reconciliation between the Kabul government and some moderates in the Taliban.
The reshuffle represented a "shift in focus right now to a different command style at a very critical period in the war," said analyst Anthony Cordesman of the Center for Strategic and International Studies in Washington.
McChrystal, the director of the U.S. military's Joint Staff, must be nominated by Obama and confirmed by the U.S. Senate before he can take up the post.
Gates also named Lieutenant General David Rodriguez as deputy commander of U.S. forces in Afghanistan. Rodriguez was lauded by Pentagon officials for a counterinsurgency effort he led in eastern Afghanistan while commanding the Army's 82nd Airborne Division.
"The way I look at this is as McChrystal and Rodriguez as a team," Gates said. "They each bring tremendous skills in a variety of areas that are very pertinent to the kind of fight that we have (in) Afghanistan. And it is their combined skill set that I think gives us some fresh opportunities looking forward."
Obama "agreed ... that the implementation of a new strategy in Afghanistan called for new military leadership," White House spokesman Robert Gibbs said.
In June 2006, President George W. Bush offered public congratulations to McChrystal, whose secret unit had tracked down Abu Musab al-Zarqawi -- the head of al Qaeda in Iraq who was killed in an Air Force bombing raid.
"VERY PUBLIC" FIRING
McKiernan, who became NATO commander in Afghanistan last June and added the top U.S. command last fall, is the chief architect of a force buildup in Afghanistan. It is expected to more than double the number of U.S. troops there to 68,000 by the end of the year from about 32,000 troops at the end of December.
Many of the extra forces will be deployed in southern Afghanistan where officials say the Taliban has made inroads because of a lack of western forces.
The new commanders face daunting problems. There are insufficient civilian development experts, inadequate Afghan forces, a dysfunctional international aid system and the self-imposed caveats that limit some NATO allies' ability to
Last week. Afghan President Hamid Karzai met Obama in the White House with the two countries at odds over civilian casualties from U.S. air strikes in Farah province. Karzai, who put the Farah death toll at 130 people, called on Washington to halt air strikes in his country but was rebuffed by American officials.
Gates acknowledged that McKiernan's departure from Afghanistan likely would mark the end of his military career.
"General McKiernan was fired in a very public manner," said Exum, the analyst with the Center for a New American Security. fight, Cordesman said. (Additional reporting by Paul Eckert; Editing by Doina Chiacu)