A detail from the FBI poster offering a reward for information leading to the capture or conviction of Saif al-Adel. [FBI]

More than six months after the United States killed al-Qaida leader Ayman al-Zawahiri in an airstrike in Kabul, Afghanistan, the terror group's leadership appears to have quietly passed to his heir apparent in Iran.

A new report from the United Nations, based on member state intelligence, concludes Saif al-Adel "is now the de facto leader of al-Qaida, representing continuity for now."

Al-Qaida itself has been quiet about the status of its leadership following the July 31 2022 strike that killed al-Zawahiri. The report points to two reasons for the silence.

Al-Adel's leadership "cannot be declared because of al-Qaida's sensitivity to Afghan Taliban concerns not to acknowledge the death of [Ayman] al-Zawahiri in Kabul and [al-Adel's] presence in the Islamic Republic of Iran," the report states.

"His location raises questions that have a bearing on al-Qaida's ambitions to assert leadership of a global movement in the face of challenges," including from its rival, the Islamic State terror group, the report adds.

Western intelligence agencies, including those in the United States, have long viewed al-Adel as a likely successor to al-Zawahiri, describing the former Egyptian special forces officer as a capable commander with vast operational experience in multiple locations.

Starting in the early 1990s, al-Adel was part of a team that provided military and intelligence training to fighters in Afghanistan, Pakistan and Sudan.

He also helped train members of al-Qaida's Egyptian affiliate, Egyptian Islamic Jihad, and Somalis who battled U.S. forces in Mogadishu from 1992 to 1994.

The U.S. indicted al-Adel in 1998 for his role in planning the deadly bombings of the U.S. embassies in Dar es Salaam, Tanzania, and Nairobi, Kenya, which killed 224 people and wounded thousands more.

Al-Adel is also a long-time member of al-Qaida's senior leadership council, the Majlis al-Shura, as well as a senior member of the group's Hittin Committee, charged with governing al-Qaida's global operations.

Initial information shared by U.N. member states seems to indicate al-Adel's tenure at the helm of al-Qaida has been somewhat smooth.

The report notes that al-Qaida's propaganda efforts have become "more sophisticated and prolific" in recent months.

And some member states indicate al-Adel has been able to solidify or increase control over some al-Qaida affiliates.

In particular, at least one member state intelligence agency said al-Adel is giving "direct instructions" to Hurras al-Din, one of al-Qaida's Syria affiliates, which is run by his son-in-law.

But current and former Western counterterrorism officials have long questioned the extent to which any al-Qaida leader could run the group from Iran.

"This is challenging for al-Qaida," a former Western counterterrorism official told VOA, speaking on the condition of anonymity following the death of former al-Qaida leader Ayman al-Zawahiri.

"Do the Iranians let him leave?" the former official asked. "It's sort of tough to be the leader of al-Qaida while stuck in a gilded cage."

Some U.S. officials, however, argue Iran is likely more than willing to help al-Qaida, despite significant religious differences between Iran's Shia regime and the terror group's origins as a Sunni group.

"Al-Qaida has a new home base. It is the Islamic Republic of Iran," then-U.S. Secretary of State Mike Pompeo warned in early 2021.

"Tehran has allowed al-Qaida to fundraise, to freely communicate with al-Qaida members around the world, and to perform many other functions that were previously directed from Afghanistan or Pakistan," Pompeo said at the time, labeling Iran as al-Qaida's new "operational headquarters."

Other U.S. officials have long argued that Iran's relationship with al-Qaida is and has been transactional in nature - that Tehran will help al-Qaida when it suits the leadership's purposes and crack down on the terror group other times.

For now, the latest public assessments from the United States suggest al-Adel may be intent on recreating al-Qaida as a fighting force to be feared, though getting there will not be without challenges.

Al-Adel "is probably interested in improving al-Qaida's battlefield capabilities, though the decentralized organizational structure is likely to impede his ability to make rapid changes," the Defense Department inspector general said in a report in November, citing information from the Defense Intelligence Agency.

The U.S. has been offering a $10 million reward for information leading to al-Adel's capture or conviction.