US forces have killed the leader of the Islamic State (IS) militant group's Afghanistan branch in a raid in the northeastern province of Kunar, the Pentagon said Friday.

"US forces killed Abu Sayed, the emir of Islamic State of Iraq and Syria -- Khorasan Province (ISIS-K) -- in a strike on the group's headquarters in Kunar Province, Afghanistan, July 11," Pentagon spokeswoman Dana White said in a statement.

"The raid also killed other ISIS-K members and will significantly disrupt the terror group's plans to expand its presence in Afghanistan."