WASHINGTON (NYTIMES) - The United States has been battling the Taleban and their militant partners in Afghanistan, the al-Qaeda terror network and the Haqqani insurgent group, for 20 years.
But the biggest immediate threat to both the Americans and the Taleban as the US escalates its evacuation at the Kabul airport before an Aug 31 withdrawal deadline is a common rival that is lesser known: the Islamic State Khorasan, or ISIS-K, the terrorist group's affiliate in Afghanistan.
Created six years ago by disaffected Pakistani Taleban, ISIS-K has carried out dozens of attacks in Afghanistan this year. US military and intelligence analysts say threats from the group include a bomb-laden truck, suicide bombers infiltrating the crowd outside Hamid Karzai International Airport, and mortar strikes against the airfield.
These threats, coupled with new demands by the Taleban for the US to leave by Aug 31, probably influenced President Joe Biden's decision on Tuesday (Aug 24) to stick to that deadline.
"Every day we're on the ground is another day we know that ISIS-K is seeking to target the airport and attack both US and allied forces and innocent civilians," Mr Biden said.
The threats lay bare a complicated dynamic between the Taleban, al-Qaeda and the Haqqani network, and their bitter rival, ISIS-K, in what analysts say portends a bloody struggle involving thousands of foreign fighters on both sides.
A United Nations report in June concluded that 8,000 to 10,000 fighters from Central Asia, the North Caucasus region of Russia, Pakistan and the Xinjiang region in western China have poured into Afghanistan in recent months. Most are associated with the Taleban or al-Qaeda, the report said, but others are allied with ISIS-K.
"Afghanistan has now become the Las Vegas of the terrorists, of the radicals and of the extremists," said Mr Ali Mohammad Ali, a former Afghan security official.
"People all over the world, radicals and extremists, are chanting, celebrating the Taleban victory. This is paving the way for other extremists to come to Afghanistan," he added.
US officials say they are preparing to combat both immediate and longer-term terrorist challenges in Afghanistan. First and foremost is the threat at the Kabul airport.
National Security Adviser Jake Sullivan said on Sunday that the threat from ISIS-K was acute and persistent, and that US commanders and other officials were taking all possible steps to thwart any attacks.
That includes striking an unlikely accommodation with the Taleban, at least temporarily, not only to allow safe passage to American citizens and Afghan allies to the airport for flights out of the country, but also to actively defend against an ISIS-K attack.
The leaders of the ISIS (Islamic State in Iraq and Syria) group in Afghanistan denounced the Taleban takeover of the country, criticising their version of Islamic rule as insufficiently hard line, and the two groups have fought in recent years.
An attack on the airport, current and former US officials said, would be a strategic blow to both the US and the Taleban leadership, which is trying to demonstrate that it can control the country. Such a strike would bolster ISIS-K's stature in the world of extremists, but that opportunity greatly diminishes after the last US Marine or soldier pulls out.
The Taleban and the Haqqani network, a militant group based in Pakistan, are essentially one and the same, terrorism experts say. Mr Siraj Haqqani has been the deputy emir of the Taleban since 2015. In turn, the Haqqanis are close, operationally and ideologically, to al-Qaeda.
"The Taleban, Haqqani network, and al-Qaeda function as a triumvirate, and one that is very much part of the same militant network, they work together hand-in-glove," said Dr Colin Clarke, a counter-terrorism analyst at the Soufan Group, a security consulting firm based in New York.
These three entities are inextricably linked, Dr Clarke said, and, in fact, have grown closer over the past decade, a trend that is likely to continue after the US withdrawal, especially as they close ranks against adversaries such as ISIS-K and the growing resistance movement in Afghanistan's north.
The ISIS-K group is one of many affiliates that the ISIS group established after it swept into northern Iraq from Syria in 2014, and created a religious state or caliphate the size of Britain.
A US-led campaign crushed the caliphate, but more than 10,000 ISIS fighters remain in Iraq and Syria, and ISIS affiliates such as the Sahel or the Sinai Peninsula are thriving.
But ISIS-K has never been a major force in Afghanistan, much less globally, analysts say. The group's ranks have dropped to about 1,500 to 2,000 fighters, about half from its peak levels in 2016 before US airstrikes and Afghan commando raids took a toll.
Since June 2020, under the ambitious new leader Shahab al-Muhajir, ISIS-K "remains active and dangerous", and is seeking to swell its ranks with disaffected Taleban fighters and other militants, the UN report concluded.
"They have not been a first-tier ISIS affiliate, but with the Afghan commandos gone and the American military gone, does that give them breathing room? It could," said Dr Seth Jones, an Afghanistan specialist at the Centre for Strategic and International Studies in Washington.
Even as the group's overall ranks have declined in recent years, Dr Jones said, ISIS-K has maintained cells of clandestine fighters who have carried out terrorist attacks.
UN counter-terrorism officials said in the June report that the ISIS group had conducted 77 attacks in Afghanistan in the first four months of this year, up from 21 in the same period in 2020. The attacks last year included a strike against Kabul University in November and a rocket barrage against the airport in Kabul a month later. ISIS-K is believed to have been responsible for a school bombing in the capital that killed 80 schoolgirls in May.
"Kabul has been the target of the majority of ISIS-K's most sophisticated and complex attacks in the past," said Mr Abdul Sayed, a specialist on extremist groups in Afghanistan and Pakistan, who is based in Lund, Sweden.
Some analysts believe ISIS-K may have links to the Haqqani network. Indeed, ISIS leader Shahab al-Muhajir is reported to have been a former mid-level Haqqani commander before defecting.
"Since many ISIS commanders and fighters were once part of al-Qaeda or an al-Qaeda franchise, it is not surprising that there should be this contact," said Professor Bruce Hoffman, a terrorism scholar at the Council on Foreign Relations. "In most cases, this contact has not produced any lasting reconciliation."
The rivalry between the Taleban and its partners and ISIS-K will continue after the last US troops leave, analysts say. And the fragile cooperation between US and Taleban commanders is already fraying, and the two could easily revert to their adversarial stances.
The US military is treating the Taleban's red line about Aug 31 seriously. The recent evacuations have been possible because of Taleban cooperation - in allowing most people to reach the airport unscathed, and in working against the threat of ISIS attacks, commanders say.
After Aug 31, military officials say, there is a real concern that at best, the cooperation with the Taleban will end. At worst, that could lead to attacks on US forces, foreign citizens and Afghan allies, either by Taleban elements or by their turning a blind eye to ISIS threats.
Mr Biden has pledged to prevent Afghanistan from again becoming a sanctuary for al-Qaeda and other terrorist groups that want to attack the American homeland. Military commanders say that will be a difficult task, with no troops and few spies on the ground, and armed Reaper drones thousands of miles away at bases in the Gulf.
In the February 2020 agreement with the Trump administration, the Taleban vowed not to allow al-Qaeda to use Afghan territory to attack the US. But analysts fear that is not happening and that al-Qaeda remains the longer-term terrorism threat.
As the UN report put it: "The Taleban and al-Qaeda remain closely aligned and show no indication of breaking ties."