A leaked NATO report in Afghanistan says the Taliban are being directly assisted by Pakistan's intelligence service, the ISI, and have widespread support among the Afghan people.
A NATO spokesman in Kabul says the report is not an analysis of the military campaign, but a compilation of the opinions of Taliban detainees.
The report also alleges that Afghan security personnel are selling arms to the insurgents.
But Pakistan's foreign ministry spokesman Abdul Basit has dismissed the allegations, saying they have no weight.
"Talk of links between the Taliban and our intelligence agencies; this is all frivolous because the entire international community knows very well that Pakistan is strongly committed to non-interference in the internal affairs of Afghanistan and the leak of this report on the eve of our foreign minister's visit to Kabul is indeed intriguing," he said.
But Pakistan is finding it harder to convince outsiders it is not helping the Afghan Taliban and giving safe haven to its leaders.
Pakistan has been accused of effectively betting that the insurgents are the strongest power in Afghanistan.
The report could be interpreted as a damning assessment of the war, dragging into its 11th year and aimed at blocking a Taliban return to power.
It could also be seen as an admission of defeat and could reinforce the view of Taliban hardliners that they should not negotiate with the United States and president Hamid Karzai's unpopular government while in a position of strength.
It could also boost the Taliban's confidence and make its leaders less willing to make concessions on demands for a ceasefire, and for the insurgency to renounce violence and break ties to Al Qaeda.
No negotiations
The Taliban chose the same day to deny that they would soon hold talks with Mr Karzai's government in Saudi Arabia to end the war.
"There is no truth in these published reports saying that the delegation of the Islamic Emirate would meet with representatives of the Karzai government in Saudi Arabia in the near future," the Taliban said on their website.
Afghan officials had suggested that talks in Saudi Arabia would be in addition to contacts in Qatar between the Taliban and the United States.
But it was never clear whether the Taliban, who have resisted talks with the Afghan government, or the Saudis, who have conditioned involvement on the Taliban renouncing Al Qaeda, would come on board.
Taliban negotiators have begun preliminary discussions with the United States in Qatar on plans for peace talks aimed at ending the war.
But they said in their statement on Wednesday that they had not yet "reached the negotiation phase with the US and its allies".
"Before there are negotiations there should be a trust-building phase, which has not begun yet," the statement said.
