An injured man is carried in Mastung, Pakistan, after a suicide bomb attack which killed at least 132 people.
Militants targeted a gathering of Balochistan Awami Party (BAP) leader Siraj Raisani in Mastung area in the troubled Balochistan province.
Another senior police official, Mohammad Tahir, said at least three policemen were among those wounded.
His return is seen as a public show of acquiescence meant to win sympathy from voters in an election that analysts predict could either spell the downfall of one of Pakistan's most charismatic leaders, or lead to years of civil unrest and political instability.
No group has so far claimed responsibility for that attack. CNN can not immediately authenticate the assertion.
The explosion was a suicide blast in which eight to 10 kilograms of explosives and ball bearings were used, reported Dawn.
"There are more than 90 bodies in six different hospitals".
The United States has strongly condemned the attacks on Pakistani political candidates and their supporters.
Chief of Army Stadium General Qamar Javed Bajwa, Commander Southern Command Lt Gen Asim Bajwa, high-ranking Army officials, Balochistan Caretaker Chief Minister Allauddin Mari, provincial ministers, Nawab Aslam Raisani and Nawabzada Lashkari Raisani were among hundreds of people who attended the funeral prayer of Nawabzada Siraj Raisani.More news: U.S. President Trump says relationship with United Kingdom is very strong
The Islamic State group has a muted presence in Pakistan but has carried out brutal attacks there in the past, including the blast at a Sufi shrine in February a year ago which killed almost 90 people.
It said that the national flag will fly at half mast on Sunday to mourn the deaths of almost 150 people in the recent terrorist attacks ahead of the general elections.
While former chief minister Akram Khan Durrani, who had also been named in Nacta list, remained safe in the attack, four of his supporters lost their lives.
But it comes amid accusations from Mr Sharif that his long-time enemies in the military establishment are undermining his Pakistan Muslim League's (PML-N) campaign in favour of Mr Khan's Pakistan Tehreek-i-Insaaf party.
The Election Commission of Pakistan has postponed polling for the constituency from where Siraj was contesting. He later visited the injured in a hospital in Bannu and said that his vehicle was damaged in the attack.
The Pakistani Taliban claimed responsibility for the attack.
Durrani belongs to an alliance of religious groups called Muttahida Majlis-e-Amal, which ruled the province between 2002 and 2008 under him.
Two of Pakistan's most popular political figures, Sharif and his daughter Maryam - his political heir - were arrested by anti-corruption police at the airport in the eastern city of Lahore moments after they arrived from London, where Sharif's wife is in a hospital receiving treatment for lymphoma.