The US says it has hit a little-known group called "Khorasan" in Syria, but experts and activists argue it actually struck al-Qaeda's affiliate Al-Nusra Front, which fights alongside Syrian rebels.
In announcing its raids in the northern province of Aleppo on Tuesday, Washington described the group it targeted as Khorasan, a cell of al-Qaeda veterans planning attacks against the West.
But experts and activists cast doubt on the distinction between Khorasan and Al-Nusra Front, which is al-Qaeda's Syrian branch.
"In Syria, no one had ever heard talk of Khorasan until the US media brought it up," said Rami Abdel Rahman, director of the Britain-based Syrian Observatory for Human Rights.
"Rebels, activists and the whole world knows that these positions (hit Tuesday) were al-Nusra positions, and the fighters killed were Al-Nusra fighters," added Abdel Rahman, who has tracked the Syrian conflict since it erupted in 2011.
AP first reported on 13 September that US intelligence officials had identified the Khorasan Group as a serious threat, in part because the group had been working with bomb makers to test new explosive devices that could go undetected by airport security.
Claims of a distinction are lost of many of Syria's rebels, who have also often rejected the world community's designation of Al-Nusra as a "terrorist" group. When Washington added Al-Nusra to its list of "terrorist" organisations, even the internationally-backed Syrian opposition National Coalition criticised the decision.
The Coalition's support for the group cooled after Al-Nusra officially pledged allegiance to al-Qaeda chief Ayman al-Zawahiri and was named the group's official Syrian branch.
But on the ground, almost all rebel groups have been willing to cooperate with Al-Nusra, seeing them as distinct from the Islamic State group (IS), which espouses transnational goals and includes many non-Syrians among its ranks.
In a statement, the rebel Supreme Military Command affiliated with the opposition National Coalition emphasised "the need to avoid targeting moderate national and Islamic forces".
And targeting Al-Nusra could even prove controversial within Washington's anti-jihadist alliance. Some key members are believed to maintain channels of communication with Al-Nusra, including Qatar, which has helped negotiate the release of prisoners held by the group.
On Tuesday, Washington made clear that, unlike the strikes against IS, none of its allies participated in the raids against al-Qaeda targets.