At least four people were killed and 32 others were injured in a bomb blast near the convoy of former Khyber Pakhtunkhwa chief minister Akram Khan Durrani in Bannu on Friday.
Durrani, who was heading back from an election rally near North Waziristan, remained safe in the remote control blast, District Police Officer (DPO) Bannu Khurram Rasheed said.
The injured were taken to District Headquarter (DHQ) Hospital Bannu for treatment, where officials confirmed the death toll had risen to four while 32 injured were undergoing treatment.
KP Inspector General (IG) Mohammad Tahir said that three police personnel were also among those injured in the attack which occurred within the limits of Haved police station.
Caretaker Chief Minister Dost Mohammad Khan condemned the incident and summoned an emergency meeting to discuss the security situation in the aftermath of the attack.
Durrani is contesting the election on NA-35 (Bannu) against Pakistan Tehreek-i-Insaf (PTI) Chairman Imran Khan on a Muttahida Majlis-i-Amal (MMA) ticket.
This is the third major attack in KP during electioneering, just days ahead of the general election 2018. On Monday, Awami National Party (ANP) candidate from Peshawar's PK-78 Haroon Bilour, and 19 others, were killed in a suicide blast.
The attack was claimed by the Tehreek-i-Taliban Pakistan (TTP) which had also claimed responsibility for 2012 attack that killed Haroon's father, Bashir Bilour.
Earlier this month, an attack on PTI candidate's office in North Waziristan's Razmak tehsil had injured 10.
Jamiat Ulema-i-Islam-Fazl (JUI-F) leader Durrani's convoy had also been targeted in an attack in 2015 when he was the federal minister for housing and works.