Sayedullah Sayed, who also leads a small political party, was fatally wounded when a bomb detonated shortly before main prayers on July 23 in the Ismail Khel of the province, provincial police chief Abdul Hakim Eshaaqzai said.

The head of the provincial hospital, Amir Badshah Rahmatzai, said nearly 20 people were brought to the hospital along with Sayed, who lost both of his legs in the attack and later died.

Violence is a major concern for Afghan voters who go to the polls on September 18 to choose from over 2,000 candidates standing for around 250 seats.

The Taliban, who frequently deny responsibility for attacks targeting mosques, said the bomb could have been the work of Sayed's rivals.

In other violence, four members of NATO-led International Security Assistance Force, (ISAF) were killed in an Improvised Explosive Device (IED) attack in southern Afghanistan, the alliance said in a statement.