The cell, known as the Lashkar-e-Khorasan, has been tasked to identify, capture and execute people working for what is described as a "web of local spies" created by the US Central Intelligence Agency, The Express Tribune newspaper quoted its sources as saying.
The Lashkar draws it strength from the Haqqani network and the Hafiz Gul Bahadur group two Taliban factions that control regions along the Afghan border, the report said.
The Tehrik-e-Taliban Pakistan led by Hakimullah Mehsud has its sympathies for the cell and provides occasional "active cooperation" to the Lashkar.
Though the exact number of members of the Lashkar is not known, a source in the tribal areas told the daily it was more than 300.
The regions where the cell works are Datta Khel, Miramshah, Mir Ali and surrounding areas where US drone strikes have been frequent.
The cell was set up last year by top commanders of the Haqqani network and the Hafiz Gul Bahadur group, which have a "tacit peace understanding" with Pakistan troops operating in South Waziristan.
The military operation in South Waziristan is aimed at rooting out home-grown Taliban striking inside Pakistan.
"In the beginning, it was a loose network with members casually going out and trying to find out who is providing information to the US... It is more organised now and they are working scientifically on the counter-intelligence line," an associate of one of the groups told the daily.
An intelligence official at the Pakistan Army headquarters in Rawalpindi and local sources in Mir Ali and Miramshah too confirmed the existence and activities of the Lashkar but appeared unaware of its structure, the report said.
The US stepped up its drone campaign in the mountainous border regions last year to eliminate what US officials called high-value targets, including top leaders of Al Qaeda and their local facilitators.
The unmanned aerial vehicles operated by the CIA to eradicate Taliban militants in Pakistan's border areas struck more than 100 times last year alone.
Though US officials do not publicly comment on the drone campaign, it is commonly known that the UAVs target a mechanical chip on the ground that spies allegedly place at Taliban hideouts.
"The Lashkar-e-Khorasan is working to find out who exactly does that and how Americans are able to find out where the mujahideen are holding a meeting or which vehicle they are travelling in," the affiliate of the Bahadur group said.
Once a suspect is caught "spying", he is taken to a Taliban court or Dar-ul-Qaza where judges or qazis ask him to explain his position.
If proved guilty, the person is executed immediately.
Two months ago, the Lashkar-e-Khorasan was behind the beheading of almost half a dozen motor mechanics in Mir Ali after US officials changed their policy of hitting compounds and instead started targeting vehicles with Taliban leaders on board.
The mechanics, mostly from Bannu district in Khyber-Pakhtunkhwa province, became a prey of the militants' outrage after they were blamed for placing chips in a Taliban Hilux car to make it a target for the US drones.