Another senior police official Kaukab Farooqi confirmed that the blast killed Bilour and injured 36 others.
Bilour had suffered serious injuries in the blast and was shifted to the hospital where he succumbed to the wounds.
The attack targeted a campaign event organised in the city of Peshawar by the Awami National Party, which has been targeted by terrorists in the past over its vocal opposition to extremist groups like the Taliban. ANP leader Iftikhar Hussain said the funeral prayers of Haroon Bilour will be offered on Wednesday at 5pm at Wazir Bagh in Peshawar.
A suicide bomb attack at a pre-election rally in the northwest Khyber Pakhtunkhwa province killed Haroon Bilour, a key leader of the secular Awami National Party, late Tuesday night, two weeks before the nationwide poll.More news: Economic Preview: There's only one dark cloud over the USA economy today
Police said the bomber struck when Bilour was about to address some 200 supporters. However, he told a private news channel that he was at home at the time of the incident. Capital City police officer Qazi Jamil told reporters that at least 54 people were wounded in the blast.
Police said that the head of the suspected suicide bomber has been found from the rooftop of a building, adding that almost eight kilogrammes of explosive material was used in the attack. Fazlullah had claimed responsibility for most of the attacks against the ANP before the 2013 election on the grounds that it had supported an army offensive against the militants.
There was no immediate claim of responsibility for the attack.
On July 4, NACTA Director Obaid Farooq while briefing a sub-committee of the Senate Standing Committee on Interior had said, "We have received as many as 12 threat alerts which are about leadership of political parties, including the Pakistan People's Party (PPP) and Pakistan Muslim League-Nawaz (PML-N), and six personalities can be targeted during elections".More news: Thai cave rescue: Four more boys extracted in second operation
Fireworks were being burst as the ANP candidate from PK 78 constituency arrived on the stage when the suicide bomber blew himself up.
Another party worker, Yaseen Khan, said a deafening explosion rocked the compound as Bilour shook hands with supporters.
People took to the social media to show solidarity with the victims of terrorism soon after the tragic news broke.
Pakistan's Chief Election Commissioner (CEC) Sardar Muhammad Raza strongly condemned the attack.More news: Iran detains teenage girl for posting dance videos on Instagram