WASHINGTON (Reuters) -- Defense Secretary Robert Gates said he hoped momentum in the Afghan war would shift to the United States and its allies by the end of this year.
The United States is pouring tens of thousands of troops into Afghanistan this year as part of a new strategy by the Obama administration to reverse gains by a resurgent Taliban and other insurgent groups.
In a shock move to shake up the war effort, Gates this week announced the dismissal of the top U.S. and NATO commander in Afghanistan, General David McKiernan. He selected Army Lieutenant General Stanley McChrystal, a special operations officer, to take over.
"With the new strategy, and with some changes and adjustments in our military approach, my hope would be that by the end of this year we will begin to see a change in momentum," Gates told the U.S. House of Representatives.
Gates said U.S. efforts in Afghanistan were "not a short-term enterprise, by any means" but he hoped that by year's end "we will be able to point to the fact that things are beginning slowly to turn in our direction."
The United States has 45,000 troops in Afghanistan now -- an increase of about 13,000 since the start of the year -- and expects to reach 68,000 later this year. U.S. allies, mainly NATO nations, have more than 30,000 troops in the country.
Most of the extra U.S. forces are due to deploy to southern Afghanistan, the most violent part of the country and heartland of the Taliban movement of Islamist militants.
Violence in Afghanistan has surged to its worst level since U.S.-backed Afghan forces ousted the Taliban from power in 2001.
The Obama administration's strategy calls for more troops, to hold onto areas once they have been cleared of insurgents, and more civilian experts to promote governance and economic development and win support from ordinary Afghans.
Admiral Mike Mullen, the chairman of the U.S. military's Joint Chiefs of Staff, said he was "very hopeful" that the United States could have "a big impact" this year and in 2010 to reverse the trend of rising violence.
But Mullen cautioned: "In the interim, we're going to have more casualties. We're going to have more that are killed and more that are wounded."
Gates and Mullen were testifying together before the Armed Services Committee of the House of Representatives.