A suicide bomber in the eastern Afghan province of Nangarhar killed at least four people, including a prominent local militia commander, considered a leading opponent of Islamic State fighters in the region, officials said on Monday.

The bomber targeted Hayat Khan, a local tribal elder and commander of local militia forces in the Behsood district of Nangarhar, Attaullah Khogyani, the provincial governor's spokesman said.

"Haji Hayat Khan was a prominent tribal elder and he was playing a important role in the fight against Daesh," said provincial council member Sohrab Qaderi, using the term often employed for Islamic State group in Afghanistan. "He was a strong barrier against Daesh expansion in Nangarhar."

The incident follows a series of attacks on targets in Nangarhar, the province on the border with Pakistan where Islamic State group first appeared in Afghanistan in late 2014.