One of the Islamic State's most feared affiliates has suffered a significant setback, though U.S. officials caution reports that the terror group was "obliterated" are overblown.
U.S. officials confirmed Thursday that Islamic State-Khorasan, as the terror group's Afghan affiliate is called, collapsed in the country's eastern Nangarhar province following months of fighting.
"Afghan government and coalition operations against the group, along with the Taliban's campaign … led to ISIS-Khorasan's collapse in Nangarhar and the surrender of hundreds of fighters to Afghan forces," a senior counterterrorism official told VOA, using an acronym for the group.
"Surrendered [Islamic State] fighters said they were told to leave Nangarhar for Kunar [province], where we assess the group still maintains a presence, as well as the northern provinces of Afghanistan," the official added.
Afghans more optimistic
The U.S. assessment contrasted with some more optimistic pronouncements from Afghan officials, who touted the victory in Nangarhar as conclusive.
"No one believed one year ago that we would stand up and remain in Nangarhar, and thank God that today we have obliterated Daesh," President Ashraf Ghani said Tuesday during a speech in Jalalabad, using an Arabic acronym for IS.
"It's not possible that they once again equip themselves in other areas of Afghanistan and threaten other parts of the country," Nangarhar Governor Shah Mahmoud Miakhel added.
Just two days earlier, Taliban officials touted their own success against the Islamic State's Afghan affiliate, calling the group's defeat in Nangarhar and Kunar provinces the result of a "decisive and large-scale" campaign that began in September.
"Over the course of the last five years, they were systematically uprooted," spokesman Zabihullah Mujahid said in a statement Sunday, adding the Taliban had "rescued the oppressed people of Nangarhar from this scourge."
Both the Taliban and Afghan government officials said almost 600 IS fighters had surrendered, along with women and children.
Still, U.S. officials said the threat from IS-Khorasan, which is thought to have between 4,000 and 5,000 fighters across Afghanistan, was far from over.
The movement of the surrendered fighters to Kunar province and northern provinces of Afghanistan "suggests ISIS-Khorasan is still active in the country despite losing territory in Nangarhar," the senior U.S. counterterrorism official said.
The U.S. Defense Department declined to discuss the statements by Afghan officials regarding the status of IS-Khorasan but said the effort to defeat the terror group would go on.
U.S. Forces-Afghanistan "will continue our work with the Afghan National Defense and Security Forces to ensure that ISIS in Afghanistan is destroyed," Pentagon spokesman Lieutenant Colonel Thomas Campbell told VOA.
'Enduring defeat' is goal
"The United States remains fully committed to the enduring defeat of ISIS, including ISIS in Afghanistan, which is critical to our national security," he added.
Over the years, IS-Khorasan has seen its fortunes waver, at one point seeing its ranks whittled to as few as several hundred fighters.
But the IS affiliate has consistently found ways to bounce back, leading defense intelligence officials to label it as an "enduring threat" to both Afghanistan and the West.
"ISIS-K has been a force that's had staying power," said Daveed Gartenstein-Ross, a counterterrorism analyst and CEO of Valens Global.
"A lot of that staying power relates to the fact that you have a growing militant landscape in Afghanistan," he said. "People who for whatever reason are disaffected with the Taliban have an alternative in ISIS-K."
There is also some thought that because of IS-Khorasan's ambition and resiliency, the estimated thousands of remaining fighters could get a boost from the terror group's core leadership in Iraq and Syria.
"With the caliphate's collapse, the core seems to be shifting some of its resources and attention to the affiliate group," said Colin Clarke, a senior research fellow at The Soufan Center, a global security analysis group. "ISIS-K in Afghanistan is very high on my list of places where the group would look to make a resurgence.
"They know the United States won't be there forever," he added. "They're laying the groundwork."