At the White House, officials backed Panetta, saying he was holding out hope that the transfer of control to Afghans could be accelerated.
"Within the context of transfer by the end of 2014, it is certainly possible — and if possible, therefore desirable — to have that transition take place earlier. But it is not an announcement of a new policy," White House press secretary Jay Carney said.
At another point Carney said, "As secretary Panetta said, it could happen and hopefully it will happen: We could do it sooner."
What this means for the pace of the withdrawal of American troops is even less clear. For now, the top U.S. commander in Afghanistan, Marine Gen. John Allen, is under orders from Obama to reduce the current total of 91,000 U.S. troops to 68,000 by September. He has been given no lower target beyond September, although some reductions are seen as likely in 2013.
British Defense Secretary Philip Hammond said the allies were united in seeing 2013 as key to getting Afghan forces in full control by the end of 2014.
"We are actually all in the same place," he said. "We all recognized that in 2013 there will be an evolution of the mission, the Afghans will be having the lead responsibility for the security throughout the whole country," he said. "But we will remain there in the combat support role and we will continue to do so, in our case, until the end of 2014, and the USA has indicated that it may go longer than that."
This week's NATO meetings began one day after a secret NATO report was leaked to the media suggesting that insurgent morale remains extremely high after more than a decade of war and that the Taliban remain confident they will defeat the U.S.-led coalition.
It also follows a series of attacks by members of Afghan forces on NATO troops or advisers. The repeated attacks have prompted worries about the degree of Taliban infiltration in the ranks of the national army and police, many of whom are considered unreliable.
There have been at least 35 attacks on international troops since 2007 by Afghan soldiers, police or insurgents wearing their uniforms, according to a tally by The Associated Press. The number rose sharply last year to 17, up from six in 2010.
Associated Press writers David Stringer in London, and Jim Kuhnhenn and Eileen Sullivan in Washington contributed to this report.
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