A classified NATO military report obtained in Afghanistan by news organizations says Pakistan's secret services are helping Taliban in directing attacks against foreign troops in Afghanistan.
The BBC and "The Times" newspaper in London quote the report as saying Pakistan's ISI intelligence agency is "intimately involved" with the Afghan insurgency.
The document alleges that Pakistan knows the locations of senior Taliban leaders and that "Pakistan's manipulation of the Taliban senior leadership continues unabatedly."
It also says the Taliban assume they will be able to retake control of Afghanistan after NATO-led forces withdraw from the country -- a move scheduled to take place by the end of 2014.
The leaked report was prepared by the U.S. military at Bagram Air Base near Kabul and given to top NATO officers in December.
An Interview With Ahmed Rashid On Leaked NATO Report
The BBC says it was based on materials obtained in 27,000 interrogations of more than 4,000 captured Taliban and Al-Qaeda operatives.
The BBC says the report quotes one senior Al-Qaeda detainee as saying "Pakistan knows everything. They control everything. I can't [expletive] on a tree in Kunar [Province in Afghanistan] without them watching. The Taliban are not Islam. The Taliban are Islamabad."
Claim Is 'Nothing New'
Pakistan's Foreign Ministry has rejected the report as "frivolous," saying Islamabad "is committed to noninterference in Afghanistan."
But Pakistani journalist Ahmed Rashid -- a noted author on Taliban and Al-Qaeda militancy in the region -- told RFE/RL that there is nothing surprising in the claim that Taliban and other militants receive support from elements within Pakistan's intelligence services.
"It's very well known amongst NATO militaries [and] amongst the U.S. military," he said. "I was told by senior American generals that they approached [former U.S.] President [George W.] Bush and Secretary of Defense Donald Rumsfeld back in 2005 about the support that the Taliban were getting from Pakistan.
"But it was ignored by Bush at that time. So this is nothing new, I think, for anyone. But the fact that it should be leaked and that it should come in such language, I suppose, is going to create quite a furor."
U.S. Pentagon spokesman John Kirby said the United States has long been concerned about "ties between elements of the ISI and some extremist networks."
But Kirby said the U.S. Defense Department had not yet seen the document reported by the BBC and "The Times."
Lieutenant Colonel Jimmie Cummings, a spokesman for the NATO-led International Security Assistance Force in Afghanistan, confirmed the existence of the document. Nonetheless, Cummings said it was "a compilation of Taliban detainee opinions" -- and not a strategic assessment.
'A New Phase' In Cooperation
The U.S. Embassy in Kabul declined immediate comment on the report. But the accusations are expected to further strain ties between Western powers and Islamabad, which has long denied backing militant groups that seek to topple the U.S.-backed government in Kabul.
Pakistan's Foreign Minister Hina Rabbani Khar, who arrived in Kabul on February 1 for a previously planned one-day visit, said Pakistan "can disregard this as a potentially strategic leak." She described the report as "old wine in an even older bottle."
Before the news reports about the leaked document, Afghan Foreign Ministry spokesman Janan Mosazai said Khar's visit was aimed at opening a "new phase" in cooperation between the two countries.
Kabul has long accused Pakistan of interfering in Afghanistan's internal affairs by helping Taliban insurgents.
But relations have been particularly poor since last September, when Aghan peace envoy and former President Burhanuddin Rabbani was assassinated -- a killing that Kabul blamed on Pakistani spies.
Kabul says the bomber who killed Rabbani was a Pakistani and has accused Islamabad of hindering the investigation.
But Kabul also is seeking Pakistan's help to convince the Taliban's senior leadership -- known as the Quetta Shura -- to join peace talks in Saudi Arabia with members of the Afghan government.
On February 1, the Taliban denied reports that its leadership would soon meet in Saudi Arabia with Karzai's envoys.
Spokesman Zabihullah Mujahid said the Taliban is "in the process of creating an understanding with the international community" through a liaison office in Qatar.
But he said the Taliban "has not reached the actual process of negotiation" with the United States or its allies. He said confidence measures must first be completed.
A senior official in Karzai's government said on January 30 that a meeting was planned in Saudi Arabia with "some" factions willing to join peace talks.
Saudi officials are reluctant to host the talks unless the Taliban renounces ties to Al-Qaeda.
Taliban Fighters Killed
News of the alleged leaked report came as Pakistan's military said warplanes killed up to 31 Taliban fighters in an attack on hideouts in the country's northwestern tribal area.
Political administrators Wajid Khan and Amir Gul said bombing operations had taken place early on the morning morning of February 1 in the Orakzai and Kurram tribal areas.
A military official speaking under condition of anonymity said four hideouts in the Orakzai district used by supporters of Taliban commanders Mullah Tufan and Moheyuddin were destroyed.
The same official said Moheyuddin might have been killed in the bombing also.
The attacks come after fierce fighting in the Kurram district
where Pakistani government troops and militants fought over a strategic mountaintop overlooking routes in Afghanistan.
Some 60 combatants were killed in that battle.
Compiled from agency reports