KHOST, Afghanistan, Oct. 5 (Xinhua) -- At least one civilian was killed and five others injured following a bomb explosion on an election campaigner's vehicle in Afghanistan southern Khost province, an official said Friday.

"The incident happened at around 11 a.m. Friday, when a roadside bomb was placed at the Mujahid square in the provincial capital Khost city, where the convoy of Naser Haqmal, a parliamentary candidate, was passing-by," Talib Mangal, the provincial governor spokesman, told Xinhua.

"One of the candidate supporters was killed and five others, including a traffic police official, wounded in the incident," the official confirmed.

The electoral campaign for the Oct. 20 Afghan parliamentary and district councils elections began on Sept. 28 across the country and will end on Oct. 17 to give way to a two-day election silence.

Violence has been on the rise as Afghan security forces struggle against a surge in attacks by militants at the time when the country is preparing for polls.

Scores of people, including seven parliamentary election runners, several electoral workers, several security force members and civilians have been killed during election-related violence since the start of the voters' registration process in mid-April.

During the elections, nearly 9 million registered voters will cast their ballots to elect members of the 249-seat lower house of parliament for a five-year term while they will also vote to elect members of the district councils.