Afghan security forces have killed Abu Muhsin al-Masri, a senior al Qaeda leader who was on the Federal Bureau of Investigation's Most Wanted Terrorists list.
Believed to be al Qaeda's second-in-command, Al-Masri was killed during a special operation in Ghazni province, Afghanistan's National Directorate of Security (NDS) said on Twitter on Saturday.
The head of the US National Counter-Terrorism Center, Chris Miller, confirmed al-Masri's death in a statement, saying his "removal .. from the battlefield is a major setback to a terrorist organisation that is consistently experiencing strategic losses facilitated by the United States and its partners."
Al Qaeda's loss of al-Masri, Miller continued, "highlights the diminishing effectiveness of the terrorist organisation".
Al-Masri has been charged in the US with having provided material support and resources to a foreign terrorist organisation, and conspiracy to kill US nationals.
The FBI declined to comment.
The al Qaeda operative, who also went by the name Husam Abd-al-Ra'uf, was an Egyptian national, according to the FBI.
Last month, US Secretary of State Mike Pompeo said fewer than 200 al Qaeda operatives remain in Afghanistan.
This month marks 19 years since the US invaded Afghanistan to topple the Taliban rulers, who had harboured al Qaeda militants who carried out the 9/11 attack.
The US has been gradually drawing down its troops from Afghanistan after striking a landmark deal with the Taliban in February.
That deal is set to see foreign forces leave Afghanistan by May 2021 in exchange for counterterrorism guarantees from the Taliban, which agreed to negotiate a permanent ceasefire and a power-sharing formula with the Afghan government.