Video obtained by CNN recorded the moment that Ukrainian International Airlines Flight 752 crashed just after taking off from Tehran's airport.
The closed-circuit footage shows a huge explosion as the plane hits the ground, leaving debris and destruction.
All 176 people aboard died when the plane crashed early Wednesday.
CNN geolocated the video near a football field in the town of Khajal Abad, southwest of Tehran, using satellite imagery and photos.
The head of the Iran's Civil Aviation Authority confirmed to CNN that the footage, timestamped 6:19 a.m. on Wednesday, is authentic.
The video surfaced online after another video, also obtained by CNN, appeared to show a missile being fired into the Tehran sky and striking an object around the same time of the plane crash.
On Thursday, leaders of Canada and Britain said they have intelligence that the Ukrainian airliner was shot down by an Iranian surface-to-air missile.
CNN reported earlier Thursday that the US increasingly believes Iran mistakenly shot down the airliner, according to multiple US officials. The working theory is based on continuing analysis of data from satellites, radar and electronic data collected routinely by US military and intelligence.