The US might have killed the Islamic State leader in Afghanistan with a drone

The Islamic State's leader in Afghanistan and Pakistan was killed in a US drone strike last month, the Pentagon said on Friday.

Hafiz Saeed Khan was the leader of IS operations across the so-called "Khorasan Province" — swaths of territory across Central Asia, Afghanistan, and Pakistan where the Islamist extremists had to jostle with other groups, like the Taliban and al-Qaeda, for territory.

He was killed in the southern Nangarhar province on July 26, "a hotbed for ISIL-Khorasan activity since the summer of 2015" the Pentagon said in a statement on Friday, using an alternative acronym for the group. "ISIL-K uses the area to train, equip, disseminate and control fighter pipelines."

The Pentagon says Khan's death is expected to disrupt those activities and dash Islamic State's hopes of expanding their operations and brand through central Asia.

The group has seemed especially determined of late to flex its muscle in the region by claiming large-scale attacks. Last week, both the Taliban and IS took credit for an attack on a hospital in Quetta, southwest Pakistan, which left 74 dead. Last month, IS also claimed an attack on a Shi'ite Hazara rally in Kabul which killed 80 people.

Khan, originally a commander with the Pakistani Taliban, pledged allegiance to IS leader Abu Bakr al-Baghdadi in 2014.

In July 2015, Afghanistan's intelligence agency erroneously claimed that Khan had been killed in a US-led coalition strike in coordination with information they provided.

Reuters reports that between January and early August of this year, US warplanes carried out almost 140 airstrikes against IS targets in Afghanistan.

In several embarrassing incidents in the past, the Pentagon has claimed that it was fairly certain that it killed militants who later turned out to be alive and well.

Follow Tess Owen on Twitter: @misstessowen