The battle, which began last week between the Taliban, also called the Tehrik-e-Taliban Pakistan or TTP, and Ansarul Islam was centered Monday in Bagh-Maidan in the strategic Tirah Valley area of Pakistan's northwest tribal region, Dawn newspaper reported.
The area is reported to be the headquarters of the Ansarul Islam, a group that earlier reports said split from the main Taliban group and is believed to be supporting pro-government tribal chiefs.
Some reports said more than 80 militants from both sides have died in fighting between the two banned groups. Several tribesmen were also said to have been killed or injured.
Dawn reported the TTP, which is different from the Afghan Taliban, claimed to have captured the heights of Haidar Kandaw, Narhaw, Ziyarath Sar, Bucha and Angori. However, the Ansars' group denied the Taliban claim about taking the hilltop areas.
Dawn quoted sources that the TTP was involved in a fierce gun battle to capture Kala Voch, another major base of the Ansars.
TTP spokesman Ehsanullah Ehsan told Dawn via telephone that his group decided to confront the Ansars after they allegedly killed Taliban volunteers and closed Taliban supply routes in breach of an agreement signed a year ago.
Dawn said Ansarul Islam also faced attacks from Lashkar-e-Islam, another banned militant group under the Taliban.
The fighting among the militants is designed to the gain control of the Tirah Valley, which is close to three of Pakistan's tribal territories.
Ansarul Islam spokesman Saadat Afridi told Pakistan's Express Tribune his group wouldn't stop fighting until the TTP is eliminated from the region.