A suicide bomber targeted an election rally in eastern Afghanistan that killed at least 13 people and wounded more than 20 others, an official confirmed Tuesday.

The bomb blast targeted the political gathering of Abdul Nasir, the Wolesi Jirga (lower house) candidate in eastern Nangarhar province, a government spokesperson Attaullah Khogyani told Anadolu Agency.

He said the assault took place in Kama district at noon.

There has been no immediate claim of responsibility for the attack in the province marred by pro-Daesh insurgency.

Afghans are set to go to the long-due parliamentary elections on Oct. 20.

Currently, a nationwide campaign for the polls is underway with the candidates holding political rallies amid grim security concerns. The Taliban have warned people against taking part in the elections.

More than 2,500 candidates will contest the Oct. 20 poll, which is seen as a test run for next year's presidential vote and a key milestone ahead of a U.N. meeting in Geneva where Afghanistan is under pressure to show progress on "democratic processes." But preparations for the ballot, which is more than three years late, have been in turmoil for months, despite U.N.-led efforts to keep Afghan organizers on track.

Some 54,000 members of Afghanistan's beleaguered security forces will be responsible for protecting more than 5,000 polling centers on election day. More than 2,000 polling centers that were supposed to open will be closed for security reasons.