The Associated Press (AP) reported that the attack, claimed Pakistani Taliban spokesman Mohammed Afridi, targeted the Tirah Valley headquarters of the rival Lashkar-e-Islam group. It was not immediately clear if those killed were all militants or if there were civilian casualties.
The two extremist groups clashes in the same area on March 2 in violence that killed 23 Lashkar-e-Islam militants, said AP.
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An April report by the Jamestown Foundation says Tirah Valley has emerged as a "flashpoint" for warring militia factions. The Pakistani government has launched five operations over the past two years specifically targeted Lashkar-e-Islam militants but has been unable to oust them from the area, the report said.
The valley is located in the mostly lawless Khyber Agency, a tribal region bordering Afghanistan and known as a haven for extremists.
Violence there has caused at least 18,000 people to flee their homes, according to AFP.