High-level talks to end the war in Afghanistan reportedly involve face-to-face discussions with the most senior Taliban commanders, who have secretly left their sanctuaries in Pakistan with the help of NATO forces.

The talks between Afghan President Hamid Karzai's closest circle and members of the Quetta shura, the Taliban leadership, also include leaders of the Haqqani network, a hard-line Afghan militant group, and Peshawar shura, a group of fighters from eastern Afghanistan, The New York Times reported.

Some leaders of the Quetta shura who oversee the Taliban war effort in Afghanistan have left their havens in Pakistan aboard NATO aircraft to attend the talks on explicit assurance that they would be protected, the paper said. Others had roads into the country cleared by allied forces.

Last week it was revealed that NATO was providing safe passage to Taliban commanders engaged in settlement talks, the clearest sign yet that the U.S. takes Kabul's discussions with the insurgents seriously.

"When the Taliban see that they can travel in the country without being attacked by the Americans, they see that the government is sovereign, that they can trust us," an Afghan official was quoted as saying.

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Previously, the Afghan government acknowledged that it has been talking with the Taliban, but discussions between the two sides were described as mostly informal and indirect message exchanges relying on mediators.

Mullah Omar, the overall leader of the Taliban, is specifically being kept out of the negotiations because of his close ties to Pakistan's intelligence agency, or ISI, which detained up to two dozen Taliban leaders earlier this year after it was discovered they were in secret talks with the Afghan government, the newspaper reported.

The Times said it was withholding the names of the Taliban officials involved in the talks at the request of the White House and to avoid retribution by those opposed to a possible peace deal.

One Afghan official told the paper that "identifying the men could result in their deaths or detention at the hands of rival Taliban commanders or the Pakistani intelligence agents who support them."

The Obama administration is a partner with the Afghan government in the talks with the Taliban, even though U.S. officials aren't sitting at the table, two top administration officials confirmed last week.

Defense Secretary Robert Gates said last week that any reconciliation between Karzai's government and the Taliban insurgents must be led by Afghans. But he told a NATO news conference that the U.S. is offering advice and following the initial talks.

The Obama administration's position is sensitive, because taking any role in talks with the Taliban risks criticism within the U.S.

"One of the principles we have established with President Karzai is transparency with one another as this process goes forward so we know what they are doing, they know what we are doing and they understand what our requirements are," Gates said. "And frankly, we share with them what we think will be in their own best interest as the process goes along."

Gates added: "It's basically a partnership as we go forward with this with clearly the Afghans in the lead. I think we're confident that we have access into this process and plenty of opportunities to make our concerns as well as our suggestions known."

In taking a public role in the current talks, the Obama administration risks being accused of negotiating with the Taliban, the radical group that harbored Usama bin Laden and his Al Qaeda network prior to the Sept. 11, 2001, attacks.

By making the U.S. role public, the administration may be signaling to a U.S. public weary of the conflict that the Obama administration is committed to ending it. Obama plans to begin withdrawing some troops in July 2011, but there won't be large numbers coming home then.

U.S. military commanders, meanwhile, may feel comfortable with the talks because they believe that the insurgency has been damaged by the arrival of tens of thousands of additional troops in recent months. Though the Taliban are far from defeated, Gen. David Petraeus, the top U.S and NATO commander, and others say that the momentum has shifted to NATO forces.

Secretary of State Hillary Rodham Clinton, meanwhile, was more cautious in her assessment of the U.S. role in the talks.

She said that the U.S. continues to insist that, as part of any peace deal, the insurgents lay down their weapons, cut ties with Al Qaeda and pledge to respect the Afghan constitution with its protections for women's rights.

While the U.S. supports what the Afghans are doing, she said, it isn't ready to make any judgment about how far the talks should go.

"There are a lot of different strains to it that may or may not be legitimate or borne out as producing any bona fide reconciliation," Clinton said.

"This will play out over a period of time," she said. "We're not yet ready to make any judgments about whether any of this will bear fruit."

The Associated Press contributed to this report.