A total of 38 people have now been killed in clashes which erupted on April 6 between the two groups.
The two groups were reported to be supporters of Khan Said Sajna and followers of the late Hakimullah Mehsud group of the Tehreek-e-Taliban Pakistan (TTP). The TTP, which was formed in 2007, is a coalition of different groups.
Militant sources suggested that differences emerged after Sajna, a senior commander, was rejected for the TTP leadership, after then-leader Mehsud was killed in a US drone strike last November.
Sajna was seen as a strong candidate to become TTP chief following Mehsud's death but the movement's ruling council at the last minute elected Mullah Fazlullah, who hails from Swat and is believed to be hiding in Afghanistan.
The government began negotiations through intermediaries with the TTP in February to try to end its insurgency.
The militant group has demanded the release of what they call "non-combatant" prisoners and the establishment of a "peace zone" from which security forces would be barred.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ