The Afghan Taliban have flatly denied reports that their representatives recently had talks with UN special envoy Kai Eide to discuss peace.
A statement by the Islamist group's ruling council described the reports as "futile and baseless rumours".
Mr Eide himself denied a report that talks were held in Dubai on 8 January and refused to comment on other dates.
In another development, an overnight Nato air strike reportedly killed four Afghan government soldiers near Kabul.
An Afghan spokesman in Wardak province said it was unclear what had happened while a US spokesman said only that international forces were investigating an "incident" in the province.
The Afghan spokesman said six soldiers had also been injured during the attack on a newly established army outpost which had, he added, been launched after foreign and Afghan forces exchanged fire on the ground.
'Machination against jihad'
On Thursday the Afghan president invited the Taliban to a peace council.
At a key Afghanistan summit in London, Hamid Karzai vowed to reach out to "disenchanted brothers".
The loya jirga assembly would bring together Afghan leaders, as well as members of civil society and clerical groups.
The one-day conference in London saw world leaders pledge $140m (£87m) to win over low-level Taliban fighters.
Delegates also said that Afghan forces could take control of security in some provinces by the end of 2010 and that the process could be completed in five years.
Taliban spokesmen have repeatedly said they have no interest in talking to Mr Karzai's government. And there was a strong denial of any talks with the UN.
"The Leadership Council considers this mere futile and baseless rumours, being a machination against jihad and Mujahideen who are waging jihad against the invaders," a Taliban statement said.
Military and diplomatic sources in Afghanistan have said they are hearing reports that some senior Taliban are tired of fighting and want a political solution.
But the BBC's Lyse Doucet says that in a situation where intelligence has often proved to be dangerously faulty, it is very hard to get the measure of what the Taliban is thinking and whether indeed this movement is divided.