An explosion targeting militants\' headquarter in northern Pakistani Orakzai tribal region bordering Afghanistan killed at least 12, security officials said Thursday. According to police officials, a compound of local militants in Orakzai tribal region was attacked early Thursday by an explosive laden vehicle that killed at least 12 persons and wounded over 14 others. Local media reports said that the militants targeted an anti-Taliban militia commander, Mullah Nabi Hanafi, in Hangu area of Orakzai. Mullah Hanafi was associated with the Tehrik-Taliban Pakistan (TTP) in the past but later after developing differences formed his own militant faction to fight against the TTP, said media reports. At first the attackers broke into the headquarters and opened fire after which the suicide bomber rammed an explosive-laden vehicle into the headquarters. The details could not be verified independently as the access to media is restricted in the area due to security reasons. Earlier, militants killed a provincial lawmaker of Pakistan Tehreek I Insaf (PTI) of Hangu and an accused member of the group of Mullah Hanafi was arrested who confessed the killing. Orakzai is one of Pakistan\'s seven semi-autonomous tribal regions in the northwest that are federally administered and facing militants\' insurgency for the last many years