Pakistan's security services are secretly aiding Afghanistan's Taliban, who assume their victory is inevitable once Western troops leave, a secret Nato document says, according to reports Wednesday.
The leaked report -- seen by The Times newspaper and the BBC -- was compiled from information gleaned from insurgent detainees and was given to Nato commanders in Afghanistan last month, the media reports said.
The "State of the Taliban" document claims that Islamabad, via Pakistan's ISI intelligence agency, is "intimately involved" with the insurgency.
The BBC said the report was based on material from 27,000 interrogations of more than 4,000 captured Taliban and Al-Qaeda operatives.
"Pakistan's manipulation of the Taliban senior leadership continues unabatedly," the report was quoted as saying.
Taliban captives revealed how Islamabad was using a web of intermediaries and spies to provide strategic advice to the Taliban on fighting Western coalition troops.
"The government of Pakistan remains intimately involved with the Taliban," the report said.
"ISI is thoroughly aware of Taliban activities and the whereabouts of senior Taliban personnel. Senior Taliban leaders meet regularly with ISI personnel, who advise on strategy and relay any pertinent concerns of the government of Pakistan.
"ISI officers tout the need for continued jihad and expulsion of foreign invaders from Afghanistan."
However, there was little evidence from the detainees that Islamabad was providing funding or weaponry.
Kabul, which accuses Islamabad of supporting the 10-year Taliban insurgency in Afghanistan, put relations on ice after the September murder of its peace envoy Burhanuddin Rabbani, which one Afghan minister blamed on Pakistani spies.
The Times quoted the report as saying the Taliban's "strength, motivation, funding and tactical proficiency remains intact", despite setbacks in 2011.
"Many Afghans are already bracing themselves for an eventual return of the Taliban," it said.
"Once (Nato force) ISAF is no longer a factor, Taliban consider their victory inevitable."
The US Department of Defense said it could not comment on the report but set out its fears about Pakistan and its influence in Afghanistan.
"We have not seen the report, and therefore cannot offer comment on it specifically," Pentagon spokesman George Little told AFP.
"We have long been concerned about ties between elements of the ISI and some extremist networks."
US Defense Secretary Leon Panetta "has also been clear that he believes that the safe havens in Pakistan remain a serious problem and need to be addressed by Pakistani authorities."
The report said there had been unprecedented interest in joining the Taliban cause in 2011 -- even from members of the Afghan government.
"Afghan civilians frequently prefer Taliban governance over the Afghan government, usually as a result of government corruption," it was reported as saying.
It said the Taliban was deliberately going soft in some areas to encourage NATO troops to leave faster, while doing local deals with the Afghan forces who take over.
Some in the Afghan security forces collaborated with the Taliban, selling arms and sharing intelligence, the report said.
The Times, in an editorial, said Pakistan was "actively hindering reconciliation" between the Taliban and Kabul with a "systematic effort" to destabilise President Hamid Karzai's government.
"The ISI emerges from this document looking considerably more villainous, even, than the Taliban itself," it said.