DEH BALA, Afghanistan — Two years ago, Pentagon officials said that American forces in the remote reaches of Afghanistan could defeat the Islamic State’s offshoot here by the end of 2017.
This month, American Special Forces in eastern Afghanistan were still fighting, with no end in sight.
During a visit by a New York Times reporter to their dusty army outpost, in the eastern province of Nangarhar, the Americans pointed out the ridges and valleys at the foot of the snow-capped Spin Ghar mountains: There, they noted, was the start of the Islamic State’s territory, in some of the most forbidding terrain in Afghanistan.
The extremist group is growing, able to out-recruit its casualties so far, according to military officials. It is well funded by illicit smuggling and other revenue streams. And in the eastern part of the country, Islamic State fighters are waging a war of terrain that the United States military can — for now — only contain, those officials said.
Interviews with six current and former American officials, who spoke on the condition of anonymity, indicated that the group is poised to expand its influence if the United States and the Taliban reach a peace settlement. The officials expressed concern that in addition to destabilizing the Afghan government, the group is becoming connected to terrorist plots beyond Afghanistan’s borders.
Deep in Afghanistan, the immediate conclusion has been to try to keep up the pressure through patrols and raids by American and Afghan Special Operations units. But the officials acknowledge that it all amounts to more of a containment effort than anything that could eradicate the Islamic State loyalists here.
Mission Support Site Jones, on the outskirts of the small village of Deh Bala, is part of the small constellation of Special Forces outposts in Nangarhar.
The Special Forces units are falling back on a counterinsurgency strategy that has been used off and on throughout 18 years of war. That means they are juggling between clearing territory alongside Afghan troops, trying to hold it, and building an Afghan force that could take over security for the district — supposedly while keeping the Islamic State contained — when the Americans eventually leave.
During a recent meeting at his outpost in Nangarhar Province, the team leader of a Special Forces unit pointed to a map of Deh Bala spread out in front of him.
“They’re always going to hold those mountains,” he said of the Islamic State. The team leader spoke on the condition of anonymity because the Pentagon insists that members of Special Operations units not disclose their names.
History supports his view: This corner of eastern Afghanistan has sheltered insurgencies for hundreds of years.
Efforts to root out militants in this area are hampered by shifting weather that can quickly close off air support, and by drastic changes in elevation — by thousands of feet — that limit the troops and equipment that can be safely ferried by helicopter.
What began in 2015 as a small group of tribes composed mostly of former Pakistani Taliban fighters who pledged allegiance to the Islamic State and its leader, Abu Bakr al-Baghdadi, soon grew into a loosely connected web of fighters and commanders spread throughout the country.
According to American military officials, fighters gradually appeared from all over the region, including Kazakhstan and Tajikistan, as well as a trickle of fighters who had fought in Iraq and Syria.
In the Afghan offshoot’s early months, Islamic State leadership in the Middle East sent money to help it along. But officials say the group has approached self-sufficiency by extorting money from locals along with smuggling timber, drugs and raw earth material, such as lapis lazuli, mined in some of the eastern provinces.
Islamic State fighters in Afghanistan are paid significantly more per month than their Taliban counterparts, in some regions by hundreds of dollars. And they have been able to keep growing.
There are an estimated 3,000 Islamic State fighters in Afghanistan, but their relatively low numbers belie the group’s growing support network of facilitators with unclear alliances and its ability to move with relative ease between Afghanistan and Pakistan, according to the officials. In recent months, Islamic State cells have appeared in the northern province of Kunduz and the western province of Herat.
But no Islamic State cell is more threatening to maintaining stability in Afghanistan than the one in Kabul, the Afghan capital.
The Islamic State groups there have become increasingly skilled in avoiding detection, the officials said, staging high-profile attacks more frequently since 2016. Last year, it carried out an estimated 24 attacks in Kabul, leaving hundreds dead or wounded and outpacing the Taliban’s Haqqani network as the most lethal group in the capital, officials said.
In Kabul and other major cities, Islamic State recruiters are siphoning disenfranchised and educated youth from universities, American officials said. And though the group has long been considered to be locally focused, there is growing concern that it is turning its sights to attacks abroad.
American officials now say that at least one Islamic State leader in Nangarhar Province helped inspire and direct the April 7, 2017, terrorist attack in Stockholm that left five people dead and at least 12 wounded when Rakhmat Akilov, an Uzbek citizen, drove a hijacked beer truck into a crowd of people. One senior intelligence official said that eight people had been arrested in the United States on accusations of providing support to the Islamic State offshoot in Afghanistan.
The group’s growing profile, particularly within Kabul, led Gen. Austin S. Miller to form a Special Operations task force soon after he took command of the American-led mission in Afghanistan last year. The task force, led by American troops, works alongside Afghan police special units to track and target Islamic State members.
The task force, according to one American defense official, could be the foundation for a counterterrorism force left behind after any peace agreement with the Taliban is reached.
But that idea remains a sticking point in the continuing peace talks in Qatar. American military officials say the Taliban have pushed back on that proposal, insisting that their fighters could handle and defeat the Islamic State loyalists.
Recently, though, the Taliban has done little to fight the Islamic State. American officials give the example of Kunar Province, where the extremist group has quietly probed into Taliban-held territory for months and where Taliban counterattacks have gained little traction. Taliban fighters there, for the most part, have continued to focus on attacking Afghan government forces rather than the competing militants, the officials said.
But not only are the Taliban mostly avoiding fighting the Islamic State, they are also feeding its ranks. Taliban insurgents serve as one of the Islamic State’s primary recruiting pools, and they often bring a wealth of combat experience with them, according to the officials.
This has made American military leadership increasingly concerned about large groups of Taliban fighters shifting to the Islamic State if a peace deal is reached. Already, the Islamic State in Afghanistan is using propaganda in preparation for a concerted recruiting campaign after any settlement.
But despite the political uncertainty, the unsettled future of American forces in Afghanistan and the potential surge in Islamic State fighters there, the slow war in Deh Bala goes on.
The Special Forces team at Mission Support Site Jones, named after Capt. Benjamin Jones, a Green Beret who was killed in Nangarhar Province in 2014, are building up their outpost, now a year old. The team has a weekly meeting with village elders, where they discuss the district’s security and the results of recent American and Afghan operations.
In a few months, the Special Forces team here will return to the United States only to be replaced by another detachment. But its remaining time will be spent the same way: juggling community outreach and training efforts with hazardous raids up into the mountains where the Islamic State shelters, in the hope that the group can somehow be contained.