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Admiral Mike Mullen, America's top military commander, refused to back down today from his position on US efforts in Afghanistan. At a press briefing he told reporters, "We're not winning..And if we're not winning, we're losing."

The sobering comment marked the second time within a week the Chairman of the Joint Chiefs expressed his concern over the current situation in Afghanistan. On Monday he told soldiers at Ft Campbell in Kentucky the same thing.

When pressed today, Mullen added, "I intend to be very clear with respect to that because I believe we're not."

But as he announced 1,500 Marines from Camp Lejeune, North Carolina would be arriving in southern Afghanistan next week, the initial elements of the 30,000 surge troops President Obama authorized on November 30th, he said, "This strategy can put us in a place where we can turn this thing around and succeed...I certainly noted Secretary Gates said the other day, 'We're in this thing to win' and that's certainly where I am. Understand that."

President Obama, in Norway today to accept his Nobel Peace Prize, renewed his pledge that the US would begin removinig troops from Afghanistan in July 2011, saying, "I've been unambiguous about this, so there should not be a debate."

And Admiral Mullen went a step further, suggesting part of that process could begin even sooner. "I believe we will transition as soon as -- as soon as we can put them -- as soon as they are in a position to take the lead. And that's really going to be up to General McChrystal. And I think by and large, it will be -- it will be district by district. And so we're by no means with this approach waiting until July 2011."

As the military deploys its forces in the coming months, Mullen told reporters, "We're all on the balls of our feet leaning forward," and added several hundred new MRAPs are already in Afghanistan with dozens more on the way, rapidly being airlifted wherever and whenever possible.

Fox News Channel's Patrick Summers contributed to this report
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