A U.S. airstrike last month killed Hafiz Sayed Khan, the head of the Islamic State's branch in Afghanistan, a Pentagon spokesman said Friday.
Khan was killed July 26 as U.S. and Afghan Special Forces conducted operations against the terror group in southern Nangarhar province, Deputy Press Secretary Gordon Trowbridge said in a statement.
His death comes as part of a major effort to crush the Islamic State, which became a growing threat in Afghanistan earlier this year.
Khan, a former Pakistani Taliban member, became head of the region's Islamic State branch, known as the Islamic State in the Khorasan Province, in 2015, pledging allegiance to the group's overall leader Abu Bakr al-Baghdadi.
Trowbridge said Khan was known to directly participate in attacks against U.S. and coalition forces, and that his network terrorized Afghans, especially in Nangarhar, which borders Pakistan.
The Afghan branch uses the Nangarhar area to train, equip, disseminate and control fighter pipelines, providing Islamic State commanders throughout Afghanistan with a continuous supply of fighters, he said
"Nangarhar province has been a hotbed for (Islamic State) activity since the summer of 2015," Trowbridge said. "Khan's death affects recruiting efforts and will disrupt (their) operations in Afghanistan and the region."
Afghan Ambassador to Pakistan Omar Zakhilwal told Reuters that the strike also killed several senior Islamic State commanders and fighters.
It is the second time in two years that Khan was believed killed by a drone. A similar claim surfaced last year from Afghan intelligence agents, but the report was never confirmed.
It was also the second reported death of a high-profile extremist in the region in four months. In May, a U.S. drone killed Mullah Akhtar Mansour, the Afghan Taliban leader, according to U.S. officials.
In January, President Obama gave the U.S. military authority to strike the Islamic State in Afghanistan and operations, including airstrikes, against them began immediately. The number of Islamic State militants in Afghanistan was estimated to be about 3,000 at its peak in January, according to coalition statistics, far fewer than the 25,000 to 35,000 Taliban militants.
Many of the Islamic State militants were former Taliban who left the organization to join the Islamic State.
Army Gen. John Nicholson, the top U.S. commander in Afghanistan, said U.S. and Afghan attacks have reduced the size of the Islamic State, also called Daesh, in Afghanistan to between 1,000 and 1,500 as a result of airstrikes and ground fighting.
"We have killed many Daesh commanders and soldiers, destroyed key infrastructure capabilities, logistical nodes, and Daesh fighters are retreating south into the mountains of southern Nangahar," Nicholson told Pentagon reporters last month.
U.S. forces are directly attacking the militants under their counterterrorism mission and Special Forces advisers are helping Afghan forces in operations against the militants as part of the overall mission to assist the country's military. Afghanistan's military recently shifted its main effort to Nangarhar and is conducting large operations there against the extremists.