It could be months before efforts to broker a peace deal between the Afghan government and the Taliban bear fruit, US defense secretary Robert Gates said in an interview aired on Sunday.
Gates, who steps down at the end of the month, said there had been contacts between United States and the Taliban in recent weeks, headed by the State Department.
"There's been outreach on the - on the part of a number of countries, including the United States. I would say that these contacts are very preliminary at this point," he told CNN.
The comments from the outgoing U.S. defense chief were aired a day after Afghan President Hamid Karzai announced the United States was in contact with the Taliban, a striking public acknowledgment of a peace initiative that has been cloaked with secrecy.
Karzai said an Afghan push toward peace talks, after nearly a decade of war, had not yet reached a stage where the government and insurgents were meeting, but their representatives had been in touch.
"Peace talks are going on with the Taliban. The foreign military and especially the United States itself is going ahead with these negotiations," Karzai said in a speech in Kabul.
The comments come as President Barack Obama prepares to announce the size and nature of the initial U.S. drawdown from Afghanistan nearly 10 years after the Sept 11 attacks.
Obama, who has increased the size of the US force by about 65,000 soldiers since he took office in early 2009, is hoping to move definitively toward ending the war as he faces sharp fiscal pressures and eyes his 2012 reelection campaign.
But Gates cautioned the peace initiative would be fraught with challenges, including locating members of the Taliban who could credibly speak for its Pakistan-based leadership.
"My own view is that real reconciliation talks are not likely to be able to make any substantive headway until at least this winter," he said.
"I think that the Taliban have to feel themselves under military pressure, and begin to believe that they can't win before they're willing to have a serious conversation."
US commanders are hailing success in pushing the Taliban out of key parts of southern Afghanistan, but violence has surged and the insurgency has become even more fierce along Afghanistan's eastern border with Pakistan.
Western military leaders say they have weakened the Taliban but predict more intense fighting ahead just as Afghan forces start to take over from the NATO-led force in some areas.
The Obama administration, which is reassessing its role in Afghanistan after a raid that killed al Qaeda leader Osama bin Laden in Pakistan, believes the Afghan war cannot be concluded without a political settlement, as distasteful as it may be to negotiate with a group it has been battling for years.
Gates said the United States had relevant experience in Iraq, where the military eventually worked side by side with Sunni tribesmen it had earlier fought. "That's the way wars end," he said.