Al Qaeda's Yemen affiliate has claimed responsibility for a fatal shooting in December at a US naval base in Pensacola, Florida.
An audio recording purportedly from Al Qaeda in the Arabian Peninsula said "we embrace the operation of the martyr hero, the daring knight Mohammad bin Saeed Alshamrani".
The recording offered no evidence that the group was behind the attack in which Alshamrani, a Saudi citizen, killed three people.
A US government source familiar with official reporting and analysis told Reuters news agency that the Trump administration did not believe Aqap's claim that the Florida shooter was acting on their behalf.
The source said that Aqap could have made the claim to divert attention after reports about the killing of its leader, Qassim Al Raymi, in a drone strike in Marib. The reports are yet to be confirmed.
One Yemeni government official confirmed that there had been a drone strike in Marib but said it was not Raymi who had been killed.
After the Pensacola attack, the US grounded all 850 Saudi pilots undergoing military training in America and restricted training to classroom-based activities while it reviewed vetting and security.
However, on January 16, the Pentagon said it would soon resume operational training.
"We're looking forward to turning that [training] back on in the coming days," Pentagon spokesman Jonathan Hoffman told a news briefing.
Saudi Arabia withdrew 21 cadets after the investigations showed they either had social media accounts containing extremist content or anti-American sentiment. At least one possessed child pornography.