The clash started between two rival Tehreek-e-Taliban (TTP) factions a few days ago and the cause of infighting was said to be interference in matters under each other's domains.
At least 10 people were killed during a clash in North Waziristan's Shawal tehsil and several were injured, Dawn News reported.
The latest clash came a day after the expiry of a 40-day ceasefire with the government.
The clashes first erupted on Sunday in Shawal between supporters of Khan Said Sajna and followers of the late Hakimullah Mehsud group.
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In a separate incident, three persons, including Sher Amanullah, a commander of the Haqqani militant network, were killed when a roadside bomb hit their vehicle near the town of Dattakhel, media reports said, quoting intelligence and militant sources.
Amanullah was said to be a close associate of Mullah Sangeen Zadran, who was blacklisted as a terrorist by the UN and US and was killed in a US drone strike in North Waziristan in September last year.
The TTP has long been driven by infighting.
Sajna had been 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 TTP has remained silent on the matter of infighting in which over 30 deaths have been reported over a couple of days.