A local government official told Express News three officials were killed in the explosion.
Police said terrorists tried to enter a courtroom where one detonated his explosives and the other was shot and killed by police, Geo News reported.
Four police officers and several lawyers were among the 30 people injured in the attack, Geo News reported.
The Khyber Pakhtunkhwa Bar Council said it would strike to protest the attack.
Security forces said the suicide jacket worn by the second bomber was defused, Express Tribune reported. It contained six kilograms (about 13 pounds) of explosives and four kilograms (about 8 pounds) of ball bearings.