Petraeus declined to provide details of the alliance's role in the clandestine talks -- discussions that he described as "preliminary." The Afghan government has previously acknowledged that it has been involved in reconciliation talks with the Taliban with some NATO help.
Petraeus told reporters at the United Services Institute on Friday that it would "not be the easiest of tasks" for a senior Taliban leader to make his way to the capital, Kabul -- unless NATO forces permitted it.
He says NATO is "aware of it and allows it to take place."
