Violence over the killing of legislator Farid Khan erupted in the restive town of Hangu in Khyber-Pakhtunkhwa.
A woman was among the injured, police officials said.
Curfew was imposed in Hangu after protestors set a petrol pump and several offices and shops on fire. The protestors also resorted to firing.
District police chief Sajjad Khan said law enforcement agencies had arrested Taliban commander Mufti Hamid and three other militants for alleged involvement in the killing.
More From This Section
Farid Khan, 42, was elected to the Khyber-Pakhtunkhwa Assembly as an independent candidate and later joined the Pakistan Tehrik-e-Insaf.
He was attacked by gunmen while he was being driven home yesterday.
Khan died instantly while his drive succumbed to his injuries in hospital. His brother Shah Nawaz was seriously injured in the attack.