In the video, three American soldiers have few resources to fight off dozens of militants armed with machine guns and grenades.
At one point in the video, a USA soldier is shot and a comrade attempts to pull him to cover behind the SUV.
The fatal mission in Niger previous year that left four American soldiers dead was not approved by senior command, a military investigation found.
You would expect the enemy not to take prisoners but you would not expect American soldiers to be so exposed without any backup.
Several Nigerien troops also were killed during the October 4, 2017, attack.
It is still unknown why the video, which was released on messaging app Telegram, was still unpublished until now.More news: Nawaz Sharif's PML-N wins big in Parliament's upper house polls
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The nine minute video is shot from the helmet cams of the tragic Americans who died on October 4 in Tongo Tongo after being attacked by 50 brainwashed jihadis. Finally, the soldier wearing the camera on his helmet falls to the ground.
The video also includes still images that allegedly show members of the Sahel-based group Jamaat Nusrat al-Islam wal-Muslimin (JNIM) pledging allegiance to IS leader Abu Bakr al-Baghdadi. The last shot shows militants surrounding him and firing at him at point-blank range.
According to reports, the military investigation into the Niger attack concludes the team did not get required senior command approval for their risky mission to capture a high-level Islamic State militant. The Pentagon's investigation into the Niger ambush and what took place is expected to be released later this week.
One reason why the general public was caught off guard is the US government has not made clear that USA mission in Niger and other African countries involves combat operations, said Bill Roggio, a senior fellow with the Foundation for Defense of Democracies think tank in Washington.
"Knowing that they were asked to try and complete and execute this type of mission with that type of equipment, I just could not believe it", Republican Congressman Marc Veasey told CBS news.
The disturbing clip, which ends before the soldiers are killed, shows the men using a vehicle and smoke flares as cover as they exchange fire with the extremists. "Why they were asked to continue to go onto this mission I think is something that we all need to find out".
"That lack of a consistent media presence may suggest that Mr. Sahraoui's unit has not been fully accepted by the Islamic State, or else that the group has not managed to establish the logistical ties that have allowed other affiliates to post statements and videos of attacks on its platforms".