The three dead were identified as, Imran Afirid, Zair Akbar and Rahat Shair.
Nek Mohammad, a tribal administration official confirmed the attack.
The security officials cordoned off the area and started a search operation.
Meanwhile, the Tehreek-e-Taliban Pakistan (TTP) claimed responsibility for the attack.
"The TTP's special 'martyrdom' unit (TSG) targeted the assistant political agent and those leaders and forces that have been tasked to implement the National Action Plan," TTP spokesperson Muhammad Khorasani said.
"Another attacker targeted the rescue team that arrived after the first blast."
Read: Three officials killed in Khyber Agency IED attack
On August 12, three officials of the army, including a captain, were killed in an improvised explosive device (IED) blast in Sandana area of Tirah Valley, Khyber Agency.
Captain Farooq of the Punjab regiment-35 was killed and two soldiers were injured when the IED exploded.
Pakistan Army has been waging a major offensive against insurgent hideouts in the tribal northwest for over a year in a bid to quell an insurgency that has raged for more than a decade.
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