The Taliban have published what they claim are the government's security plans for a national convention in Kabul that 2,000 elders are expected to attend this week to discuss Afghanistan's future relationship with the United States and peace talks with the insurgents.
If the documents are genuine, their publication would be the latest in a series of embarrassments for the Afghan government and its security forces at the hands of rebels who Nato claims are on the run.
The plans published on the rebel group's Voice of Jihad website include a detailed satellite map of western Kabul, where the convention, or Loya Jirga, is scheduled to take place later this week, under the awnings of a giant tent donated by Germany.
Other pages from the purported plan include existing phone numbers for security personnel and what looks like the signature of Lieutenant General Curtis Scaparrotti, the deputy commander of US forces in Afghanistan.
Nato said the signature was a forgery, and a spokesman for Afghanistan's Interior Ministry denounced the Taliban claims as a plot designed to intimidate elders coming to the Loya Jirga, convened by President Hamid Karzai to map out Afghanistan's future ties with the US.
The US and Afghanistan are negotiating a strategic partnership that is likely to see an American agreement to fund Afghanistan's security forces in exchange for access to long-term bases from which US forces can conduct counter-terror operations.
Mr Karzai also wants to assess what future Afghanistan's peace programme has in the wake of the assassination of its figurehead, former President Burhanuddin Rabbani in September by a suspected Taliban assassin.
Opposition politicians have called for a boycott of the Jirga, which they say will lend Karzai a veneer of popular support and undermine democratic institutions that are supposed to act as a check on the presidency.
The Taliban, meanwhile, have vowed to disrupt it with such favoured tactics as multiple suicide attacks, rocket bombardment and by infiltrating the ranks of the army and police.
On Voice of Jihad, the rebels boast that they have acquired the convention's security plans "by means of its personnel embedded inside the enemy ranks". The statement gloats that "these important secrets which you will see in the below pages have been acquired by Mujahideen of Islamic Emirate [the name the Taliban choose to go by] from two Ministries and from the special security corps of the government".
The statement continues: "Our upcoming attacks will become even more lethal and precise with the acquisition of such intelligence material, if Allah wills it. It is also necessary to remind those people who want to participate in this Jirga... that their lists and actions will be noted down and they will be put on trial. Then they will be humiliated."