Taliban militants say they have suspended preliminary talks in Qatar with the United States aimed at building confidence for eventual Afghanistan peace negotiations.
A Taliban statement on March 15 accused the U.S. of having a wavering position that was an obstacle to progress. It said U.S. positions and statements on the negotiations had been "shaky, erratic, and vague."
It also said the Taliban rejects talks with Afghan President Hamid Karzai's government.
In Washington, the White House responded by saying it remains committed to supporting an Afghan-led reconciliation process.
White House spokesman Jay Carney said there is "no likely resolution to the conflict in Afghanistan without a political resolution."
Carney also denied Taliban accusations that U.S. statements had been erratic and insisted that Washington had been consistent in its message.
U.S. State Department spokesman Victoria Nuland stressed that an Afghan-led peace process is essential.
"We still feel that if there is a process that can be supported that we ought to do that," she said. "We remain prepared to continue these discussions. Our only goal is get the Afghans to sit down together."
The Taliban statement deals a blow to the U.S.-led coalition's hopes of a negotiated agreement to end the decade-long war in Afghanistan.
Taliban and U.S. representatives had been discussing the possible release of five Taliban detainees at Guantanamo Bay and the establishment of a Taliban political office in Qatar for future peace negotiations.
Karzai Wants Security Handover
In Kabul, meanwhile, Afghan President Hamid Karzai called for NATO-led forces to leave Afghan villages after a U.S. soldier on went on a shooting rampage and killed 16 Afghan civilians on March 11.
On March 15, Karzai's office quoted the president as telling visiting U.S. Defense Secretary Leon Panetta that NATO-led international forces should "be withdrawn from villages and relocated in their bases."
The statement said Afghan security forces "have the ability to keep the security in rural areas and in villages on their own."
It was not immediately clear how many U.S. bases could be affected by Karzai's demand, as the United States previously disbanded a number of outposts in a bid to concentrate on securing major towns from Taliban influence.
Karzai's spokesman Aimal Faizi said the Afghan president also told Panetta on March 15 that his government wants to take control of security from NATO forces in 2013, not 2014, as previously planned by Washington.
There was no immediate response from NATO or Panetta on Karzai's demand.
But Panetta later told reporters he was "confident" both sides could work out a treaty allowing a U.S. military presence in the country beyond 2014.
The talks between Karzai and Panetta followed the March 11 massacre by a U.S. soldier of 16 villagers in southern Kandahar Province.
Panetta indicated that Karzai accepted his promise that the suspect would be brought to justice:
"I again pledged to [President Karzai] that we are proceeding with a full investigation here and that we will bring the individual involved to justice, he accepted that," Panetta said.
Afghan legislators had earlier expressed outrage that the U.S. military flew the soldier out of the country, to a detention center in Kuwait, despite their demands that he be tried in Afghanistan by an Afghan court.
Under treaties signed between Kabul and the United States, the case technically falls under the jurisdiction of a U.S. military court.
Panetta has said previously that the suspect, if convicted could face the death penalty under U.S. law
With Reuters, AP, AFP, and dpa reporting