Afghan special forces stormed an isolated mudbrick house in a Taliban-controlled district of Ghazni Province in October, killing six suspected militants -- including Husam Abd-al-Ra'uf, the No. 2 figure in the Al-Qaeda terrorist network.
The Egyptian national, also known as Abu Muhsin al-Masri, was on the FBI's Most Wanted Terrorists list for conspiracy to kill U.S. citizens.
Just weeks later, Afghan forces killed another senior Al-Qaeda leader named Mohammad Hanif in a Taliban-controlled district of the southwestern Farah Province.
Such high-profile killings have shown the Taliban still hosts Al-Qaeda more than 19 years after U.S.-led forces toppled the Taliban regime for harboring Al-Qaeda founder Osama bin Laden following the September 11 terrorist attacks against the United States.
Since late 2001, the United States’ core strategic aim in Afghanistan has been to ensure that terrorist groups cannot launch attacks against the United States again from Afghan territory.
Under a deal struck with the United States in February 2020, the Taliban pledged to end its cooperation with Al-Qaeda and start peace talks with the Afghan government.
In exchange, U.S. troops were meant to leave Afghanistan by May 2021.
The Taliban has opened talks in Doha with Afghan government delegates about a possible peace settlement.
But it remains unclear whether the Taliban is willing or able to end its deep links with Al-Qaeda -- a decades-old relationship forged through ideological sympathies and a history of shared battlefield struggles.
Now, the Taliban’s apparent failure to fulfil that obligation is complicating efforts to end the war in Afghanistan.
The roots of Al-Qaeda date from the Soviet occupation of Afghanistan in the 1980s when bin Laden and future Taliban leaders fought alongside U.S.-backed mujahedin factions that were battling Soviet forces.
After the Soviets withdrew from Afghanistan in 1989, bin Laden and other Saudi fighters in the conflict returned to Saudi Arabia. Then, bin Laden and his Saudi allies moved to Sudan before returning in 1996 to Afghanistan, where they were offered accommodation and protection by the Taliban regime.
In return, Al-Qaeda provided crucial military training, funds, and weapons to the Taliban -- which had emerged just a few years earlier in Kandahar and had seized large swaths of Afghan territory following a brutal civil war between rival mujahedin factions.
From its sanctuaries in Afghanistan, Al-Qaeda orchestrated a series of attacks against U.S. targets around the world, culminating in the September 11, 2001 terrorist attacks in the United States that killed nearly 3,000 people.
A U.S.-led military campaign since then has severely weakened Al-Qaeda, which is now thought to have only a few hundred fighters remaining in Afghanistan.
But observers say the terrorist network remains a crucial part of the Taliban insurgency, with Al-Qaeda figures serving as military advisers, explosives experts, and instructors on their extremist interpretation of Islam.
“It will be extremely difficult to untangle these two groups,” says Weeda Mehran, an Afghanistan expert at Britain’s University of Exeter. “Their ties have been cemented through factors such as shared history, close collaboration, and shared patrons that, at the very least, will take time and effort to be severed.”
A United Nations monitoring team said in February that it had evidence of Al-Qaeda fighters who are still training and advising the Taliban.
It said Al-Qaeda members are often embedded in Taliban units to act as military advisers for key operations.
The U.N. monitoring team also said the Taliban had “regularly consulted” with Al-Qaeda during negotiations with the United States last year and “offered guarantees that it would honor their historical ties.”
Mehran expects that the Taliban will continue to maintain its ties to Al-Qaeda even if an intra-Afghan peace deal is agreed upon.
“Certain elements of the Taliban will continue with Al-Qaeda," Mehran says. "Up to a certain degree, this might be tolerated by everyone as this can be a buffer against more pernicious groups in the region, such as Islamic State.”
In fact, the 2020 U.S.-Taliban deal does not include an explicit Taliban commitment to break off ties with Al-Qaeda.
The agreement states that the Taliban “will not allow any of its members, other individuals or groups, including [Al-Qaeda], to use the soil of Afghanistan to threaten the security of the United States and its allies.”
It also says the Taliban must “send a clear message” to Al-Qaeda that they “have no place in Afghanistan,” not to “cooperate” with them, and to “prevent them from recruiting, training, and fundraising.”
It also says the Taliban cannot "provide visas, passports, travel permits, or other legal documents” that allow Al-Qaeda members to enter Afghanistan.
Ibraheem Bahiss, an independent Afghan research analyst, says the Taliban has made “some incremental steps” in fulfilling its commitments.
Bahiss says the Taliban has “taken a very strong stance” toward the rival IS militants, although it has been “less forceful” with other transnational groups such as Al-Qaeda.
In February, the Taliban issued instructions to its members to avoid recruiting or harboring foreign fighters and stipulating punishment for violators. It is unclear if those rules have been implemented.
Observers say it will be difficult to determine if the Taliban has met all of its obligations. The U.S.-Taliban deal includes secret annexes while the publicly available text contains ambiguities that make it difficult to verify compliance.
It is unclear, for example, if the Taliban’s commitments extend to territories where they have full control or include contested areas. The definition of control is also vague. The distinction is significant because nearly half of Afghanistan’s districts are contested by the Taliban and control over specific territory is often changing.
The Taliban’s obligation to prevent Al-Qaeda from using Afghan soil to plot and mount attacks on the United States and its allies is the most specific stipulation in the deal. But proving they have failed to comply with that obligation also is difficult.
“The Taliban has the luxury of plausible deniability,” says Michael Kugelman, deputy director of the Asia Program at the Washington-based Wilson Center. “It's easy to find examples of the Taliban providing space to the group. It's a lot harder to point to examples where the Taliban is providing space to Al-Qaeda members that are plotting attacks on the United States. There's no smoking gun.”
Kugelman says the difficulty of verifying Taliban compliance on its counterterrorism commitments is a “reflection of a flawed deal.”
In February, a report to Congress by the Office of the Inspector General on the U.S. military mission in Afghanistan said “it was unclear whether the Taliban was in compliance with the agreement, as members of Al-Qaeda were integrated into the Taliban's leadership and command structure.”
The Pentagon warned in July that that while Al-Qaeda currently poses a “limited threat” to the United States in Afghanistan, the group is resilient and its interest in attacking U.S. and Western targets “persists.”
Ultimately, the question of whether the Taliban has met its obligations regarding Al-Qaeda will be a political one rather than a legal interpretation of the agreement.
“It will be determined by the United States at its sole discretion and with view to overarching political considerations,” Bahiss says.
Analysts say President Joe Biden could threaten to hold up the withdrawal from Afghanistan of the remaining U.S. troops if there is no indication, or insufficient evidence, that the Taliban has ended its cooperation with Al-Qaeda.
Biden has long seen the war in Afghanistan through a counterterrorism lens. Before assuming office in January, he said Washington should pull out of the country, save for a relatively small number of troops -- “several thousand” -- to fight Al-Qaeda and IS militants.
If Biden’s concerns are not addressed, observers say he could retain a small counterterrorism force that would remain in Afghanistan beyond a major military withdrawal -- even though the existing U.S.-Taliban deal includes no provision for a continued U.S. military presence.
But his administration has been surprisingly silent about Al-Qaeda in its messaging on Afghanistan. A new U.S. peace proposal and accompanying draft peace deal submitted to the Afghan government and the Taliban in late February was largely quiet on counterterrorism issues.
Kugelman says it could be an issue of sequencing, with Washington first looking to focus on reviving the Afghan peace process, building a regional consensus for peace, and incentivizing the Taliban to reduce violence.
“The United States has not downgraded Al-Qaeda as a concern,” Kugelman concludes.