Image caption Thirty-two-year old Salem Mohammad Achakzai was campaigning on a platform for "positive change"

A young Afghan parliamentary candidate was among eight people killed in a suicide attack in the southern province of Helmand, officials say.

The bomber blew himself up inside Salem Mohammad Achakzai's office in Lashkar Gah city. Eleven others were injured.

It was the second suicide blast targeting a parliamentary candidate during the campaign for the 20 October election.

Both the Taliban and the Islamic State group have urged a boycott of the vote.

No group has, however, said it carried out the latest bombing, which President Ashraf Ghani has blamed on "terrorists", news agency AFP reports.

Helmand has long been a stronghold for the Taliban, who were removed from power in a US-led invasion in 2001.

Omar Zwak, the Helmand provincial governor's spokesman, said the attack happened inside the Achakzai campaign office at 14:30 local time (10:00 GMT).

Achakzai, 32, was a local businessman and a first-time candidate campaigning on a platform for "positive change".

His death takes the number of candidates killed in targeted attacks to six, AFP reports.

At least 2,500 candidates are contesting the election.

Preparations for the parliamentary election - seen as a test run for next year's presidential vote - have been beset by challenges for months.

Allegations of fraud, bureaucratic inefficiency and the last-minute use of biometric verification of voters threaten to derail the process, which is three years late.

Some 50,000 Afghan security forces will be responsible for protecting more than 5,000 polling centres on election day.