The Islamic State, IS, has published a video purporting to show an ambush in Niger in which four US soldiers were killed last October.
It is not clear why the release of the video - via an IS outlet on messaging app Telegram - was delayed until now.
The video consists mainly of raw footage, including images apparently filmed using a helmet camera belonging to one of the soldiers.
The video seems to suggest that the attack was carried out by IS militants.
The deaths became a major talking point in the US when the widow of one of the soldiers, Army Sgt La David Johnson, said President Donald Trump had made her cry during a condolence phone call by suggesting her husband "knew what he signed up for".
The president later said Ms. Wilson's account of the call was "totally fabricated".
The propaganda film begins with still images showing an alleged pledge of allegiance to IS leader Abu Bakr al-Baghdadi by members of the Sahel-based group Jamaat Nusrat al-Islam wal-Muslimin (JNIM).
JNIM was formed from a number of West African jihadist groups in March 2017 and originally had pledged allegiance to al-Qaeda.
This alleged switch to IS was reported last month by a number of analysts, but it had not been promoted by IS outlets on social media.
The graphic video shows several armed militants walking and running in a desert area, apparently heading for the ambush, reports BBC Monitoring.
The soldiers are seen driving away in a white vehicle, with coloured smoke grenades providing cover.
After a cut in the video, the US soldiers are seen around another vehicle, with one soldier driving and the other two walking beside while seemingly firing at their attackers.
Then, one of the soldiers drops to the ground. The man wearing the helmet camera tries to raise the fallen man.
The soldier driving the vehicle jumps out and helps drag the soldier to cover, before he and the camera-wearer run into the scrub.
While running, the soldier wearing the camera falls to the ground. The footage ends with the camera unmoving, and militants surrounding the soldier, firing at point-blank range.