Security concerns surrounding the elections have combined with allegations of widespread rigging to suck the life out of electioneering, widely seen as decisive for the future of President Musharraf.
"It was a suicide attack, there were people outside the candidate's house and they were waiting for food when this man attacked. I have been told 27 people died and the number of injured is quite high," interior minister Hamid Nawaz told AFP.
"It is a very unfortunate incident. Maximum security measures are in place for the 17th and 18th (of February) and the campaign is going to end tonight," he added. A further 93 people were wounded in the blast, interior ministry spokesman Brigadier Javed Cheema said.
Security officials earlier told AFP that a suicide bomber attacked a Pakistan People's Party meeting outside the office of candidate Riaz Shah. His family said the candidate was safe. "A man with long hair drove a car into the crowd and blew himself up. There were bodies and blood everywhere," witness Laiq Hussain told AFP. In a separate incident in Bajaur militants blew up a polling station with a timebomb, police said.