Nato's top commander in Afghanistan has said increased troop levels could bring a negotiated peace with the Taliban.
US Gen Stanley McChrystal told the UK's Financial Times newspaper that there had been "enough fighting".
He said a political solution in all conflicts was "inevitable". His remarks came as the top UN envoy in Kabul said it was time to talk to the militants.
Afghan and Pakistani leaders are in Turkey to discuss tackling the Taliban-led insurgency in their countries.
This is the fourth such meeting initiated by Turkey, which has offered to broker talks between the Afghan government and the Taliban.
Both Afghan President Hamid Karzai and his Pakistani counterpart, Asif Ali Zardari, will attend an international conference on Afghanistan in London on Thursday.
'Focus on the future'
"I'd like everybody to walk out of London with a renewed commitment, and that commitment is to the right outcome for the Afghan people," Gen McChrystal told the Financial Times.
He said the arrival of the extra 30,000 US troops pledged by President Obama and the additional 7,000 troops promised by other Nato countries should deliver "very demonstrably positive" progress in 2010.
But he warned that the level of Taliban violence could increase sharply this year.
The Taliban wanted to create the perception that Afghanistan was on fire, and that President Karzai and his Western allies could not cope, Gen McChrystal said.
However, if the new US-led strategy was successful, the militants "could look desperate" in a year's time, he said.
"I think they will look like an entity that will be struggling for its own legitimacy... I think they will be on the defensive militarily, not wiped out."
On the issue of reconciliation, Gen McChrystal said: "I believe that a political solution to all conflicts is the inevitable outcome. And it's the right outcome."
Asked if he thought senior Taliban could have a role in a future Afghan government, he said: "I think any Afghans can play a role if they focus on the future, and not the past.
"As a soldier, my personal feeling is that there's been enough fighting," Gen McChrystal added.
'Time has come'
In an interview with the New York Times, United Nations special representative Kai Eide called for some senior Taliban leaders to be removed from a UN list of terrorists, as a prelude to direct talks.
"If you want relevant results, then you have to talk to the relevant person in authority," Mr Eide said. "I think the time has come to do it."
President Karzai recently told the BBC that he planned to introduce a scheme to attract Taliban fighters back to normal life by offering money and jobs.
He said he would offer to pay and resettle Taliban fighters to come over to his side.
Mr Karzai said he hoped to win backing for his plan from the US and UK at the London conference.
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