US forces killed 11 members of al Qaeda in two air strikes near Idlib in Syria, this month, including a former ally of Osama Bin Laden, the Pentagon says.
Captain Jeff Davis, a spokesman, said 10 operatives had been killed in a single strike last Friday.
A second strike on Saturday killed Abu Hani al-Masri, who had close ties to the late al Qaeda leader, he added.
Masri is said to have set up and run al Qaeda training camps in Afghanistan during the 1980s and 1990s.
He also had close ties to Ayman al Zawahiri, who became the leader of al Qaeda when Bin Laden was killed by US forces in 2011.
"These strikes disrupt al-Qaeda's ability to plot and direct external attacks targeting the US and our interests worldwide," said Capt Davis.
Al Qaeda's influence in Syria operates largely through an affiliate jihadist group, Jabhat Fateh al-Sham (JFS), formerly known as al-Nusra Front.
The group announced in mid-2016 that it was no longer affiliated with any external group, prompting speculation that it had cut ties with al Qaeda, although the latter group was not mentioned by name.
It is thought that the JFS leadership structure is still intertwined with al Qaeda.
The group, which at one stage controlled most of Idlib province, was one of those excluded from the ceasefire negotiated by Russia and Turkey in December.
Its headquarters in Idlib city was reportedly targeted in air strikes on Wednesday, which are said to have killed 23 people, including civilians.
It was unclear whether those air strikes had been carried out by Syria's government, its ally Russia or the US-led coalition.
A US operation against al Qaeda in Yemen last week - the first military action authorised by President Donald Trump - resulted in the death of a Navy Seal commando and up to 16 civilians, including children, according to reports.
Trump's administration declared the operation a success, saying it had yielded valuable intelligence.
However, Senator John McCain, who is himself a Republican, suggested the raid had failed because of the death of the soldier and civilians, and the loss of an Osprey MV-22 plane.
He added that a mission's failure did not detract from "the heroism of men and women who serve".