"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."
First emerging in 2015, ISIS-K overran large parts of Nangarhar and Kunar provinces, near the Pakistan border, but their part in the Afghan conflict had been largely overshadowed by the operations against the Taliban.
Afghan and US forces had killed Abu Sayed's two predecessors atop the group's Afghan branch -- Hafiz Saeed in July 2016 and Abdul Hasib in late April of this year, the Pentagon said.
At the time, the US military had said Hasib's death would "help reach our goal of destroying them in 2017."
The compound used by Hasib in Nangarhar province was not far from the spot where on April 13, the US military dropped the largest non-nuclear bomb it has ever used in combat, hitting ISIS positions.
The deployment of the so-called Mother Of All Bombs (MOAB) killed at least 95 jihadists, according to the Afghan defense ministry, but fighting in the area has continued.
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