The leader of the Islamic State terror group cell that carried out the August 2021 bombing that killed 13 U.S. troops and about 170 Afghan civilians is dead, slain during recent clashes with Afghanistan's ruling Taliban.
U.S. officials, who initially confirmed the death to VOA on the condition of anonymity in order to discuss the intelligence, declined to name the cell leader or say when or where he was killed.
It was also unclear whether the individual was targeted by the Taliban or was killed as a result of ongoing fighting between the two groups. In a statement the U.S. Defense Department said, "The United States was not involved in this operation."
National Security Council Coordinator for Strategic Communications John Kirby confirmed the cell leader's death in an email to VOA, calling it "another in a series of high-profile leadership losses" that the group has suffered so far this year.
Kirby said the cell leader was a key official "directly involved in plotting operations like Abbey Gate," adding that the IS affiliate's ability to launch additional attacks against U.S. interests has been diminished due to a series of setbacks inflicted by the U.S. and its partners, and even the Taliban.
Confirmation of the IS cell leader's death came as multiple U.S. media outlets reported U.S. officials were contacting family members of the 13 U.S. troops killed in the attack on Kabul Airport's Abbey Gate to inform them of the development.
The attack on Abbey Gate in the waning days of the U.S. withdrawal from Afghanistan left a lasting mark on the United States.
Following the attack, U.S. President Joe Biden promised justice for those killed.
"To those who carried out this attack, as well as anyone who wishes America harm, know this: We will not forgive," Biden said in a nationally broadcast address. "We will hunt you down and make you pay."
But since the withdrawal, the U.S. has carried out just one counterterrorism strike in Afghanistan: Last July, a drone strike killed Ayman al-Zawahiri, the leader of IS rival al-Qaida, as he hid in the capital of Kabul.
U.S. Central Command, which oversees U.S. military operations in South Asia, has acknowledged two other operations but said the details remain classified.
In the meantime, the Islamic State's Afghan affiliate, known as IS-Khorasan or ISIS-K, has spread across the country, with cells in the Afghan capital and a growing number of provinces.
Intelligence shared in a United Nations counterterrorism report earlier this year estimated IS-Khorasan has between 1,000 and 3,000 fighters but cautioned that the affiliate was looking to expand its reach, pumping out propaganda in multiple languages, including Persian, Tajik, Uzbek and Russian.
Top U.S. military and intelligence officials have also grown increasingly wary of the IS Afghan affiliate.
Last month, CENTCOM Commander General Michael Kurilla told U.S. lawmakers that IS-Khorasan has set its sights on striking the West.
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"They can do external operations against U.S. or Western interests abroad in under six months with little to no warning," Kurilla said, adding the likely targets would be in Asia or Europe.
U.S. intelligence agencies have likewise sounded alarms about IS-Khorasan's ambitions.
Defense Intelligence Agency chief Lieutenant General Scott Berrier said early last month that it was only "a matter of time before they may have the ability and intent to attack the West."
This past January, National Counterterrorism Center Director Christine Abizaid called IS-Khorasan the "threat actor I am most concerned about."
U.S. officials have also expressed little faith in the ability of the Taliban to make good on their pledge to contain IS-Khorasan.
"The Taliban doesn't have the precision to go after individuals," CENTCOM's Kurilla told U.S. lawmakers.
"They [Taliban] will do large, sweeping clearance operations," he said, noting such operations are only "disruptive to a point."
The White House's Kirby, late Tuesday, defended U.S. efforts to target IS-Khorasan, despite the lack of strikes.
"We have made good on the president's pledge to establish an over-the-horizon capacity to monitor potential terrorist threats, not only from in Afghanistan but elsewhere around the world," he said.
As an example, Kirby pointed to the U.S. counterterrorism operation this past January in Somalia that killed IS operative Bilal al-Sudani, who played a key role in funding IS-Khorasan.
IS-Khorasan was quick to claim the August 26, 2021, attack on Kabul Airport's Abbey Gate, using it to build momentum as the U.S. left.
But despite initial claims by U.S. military officials that the bombing was part of a coordinated attack on the airport, a subsequent Pentagon investigation determined that was not the case.
"This was not a complex attack," Army Brigadier General Lance Curtis told reporters in February 2022, detailing the investigation's findings. "It was a single blast, and it did not have a follow-on attack."
According to the report, all of the death and damage was caused by the single bomb, which investigators said was powerful enough to send shockwaves through the tightly packed crowds at Abbey Gate, spreading 50 meters from the detonation site.
The Abbey Gate bombing put the U.S. military in Afghanistan on heightened alert until the very end of the withdrawal, and possibly contributed to a botched airstrike three days later that killed as many as 10 civilians, including an aid worker and seven children.
"The degradation of ISIS in the region continues to be a top priority for this administration," State Department Principal Deputy spokesperson Vedant Patel told reporters during a briefing earlier Tuesday. "It's something that we continue to work collectively on with our allies and partners and others in the region."