WASHINGTON ( CNN ) -- The United States replaced the top allied commander in Afghanistan on Monday , deciding `` fresh eyes '' are needed to reverse the course of the seven-year-old war there , Defense Secretary Robert Gates said . Gen. David McKiernan is being replaced as commander of NATO forces in Afghanistan . Gen. David McKiernan , who has held the post for less than a year , will be replaced by Lt. Gen. Stanley McChrystal , a former special operations chief , Gates announced . He told reporters there was `` nothing specific '' behind McKiernan 's removal , but that `` new leadership and fresh eyes '' were needed in a war that Washington admits it is not winning . `` We have a new strategy , a new mission and a new ambassador . I believe that new military leadership also is needed , '' Gates said . McKiernan will remain in place until the Senate confirms the appointments of McChrystal and his designated deputy , Lt. Gen. David Rodriguez . Both have previous experience in Afghanistan and more history with counterinsurgency operations than McKiernan . Adm. Mike Mullen , the chairman of the Joint Chiefs of Staff , said in March that the Afghan war `` is winnable , but we are not winning . '' Since taking office in January , President Obama has committed an additional 21,000 troops and trainers to Afghanistan in an effort to battle a resurgent Taliban and signed off on McKiernan 's replacement , the White House said . `` The president was grateful for and impressed by the leadership that Gen. McKiernan demonstrated in calling for additional resources for the fight in Afghanistan , '' the White House said in a written statement . `` This change of direction in Afghanistan in no way diminishes the president 's deep respect for Gen. McKiernan and his decades of public service . '' And in a statement of his own , McKiernan said the U.S. military `` must remain committed to the great people of Afghanistan . '' `` While the Taliban and other terrorist groups offer only lies and fear , our continued efforts promote freedom and hope , '' he said . The United States invaded Afghanistan in October 2001 in response to the September 11 , 2001 , al Qaeda attacks on New York and Washington . It quickly displaced the ruling Taliban , which had allowed al Qaeda to operate from its territory , but the top al Qaeda and Taliban leaders slipped the noose and remain at large . A total of 1,135 allied troops , including 678 Americans , have been killed in Afghanistan since the war began . The Taliban . meanwhile , has taken root in neighboring Pakistan , which launched a new offensive against the militants last week . McChrystal and Rodriguez `` bring a unique skill set in counterinsurgency to these issues , and I think that they will provide the kind of new leadership and fresh thinking that the admiral and I have been talking about , '' Gates said . Gates ' announcement came less than a week after Obama met with the presidents of Afghanistan and Pakistan and pledged a more coordinated effort to defeat the insurgents . Afghanistan , meanwhile , has been complaining about civilian deaths in U.S. airstrikes , including one last week that killed dozens of people . But Gates said civilian casualties are down in Afghanistan compared with last year , while U.S. and allied casualties are up by 75 percent . `` There is a tremendous effort going on , on our part to try and avoid civilian casualties , '' he said . `` But figuring out how to come out better on the strategic communications side of this is an ongoing challenge for us . '' CNN 's Barbara Starr contributed to this report .
NEW : Senate Secretary says `` fresh eyes '' are needed to reverse course of war . Gen. Stanley McChrystal to stay in post until Defense confirms successor . Gates speaks of Stanley McChrystal 's `` long and distinguished career '' Slated to take over for McKiernan is Lt. Gen. McKiernan .