Iran says it has arrested the person who filmed the footage showing an Ukrainian passenger plane being shot down by a missile.

It is believed the person being detained will face charges related to national security.

However, an Iranian journalist based in London who initially posted the footage insisted that his source is safe, and that the Iranian authorities have arrested the wrong person.

The man who obtained the security camera footage reportedly ​fears being arrested by authorities and has gone into hiding.

Iran admitted that its military had accidentally fired a missile at Ukraine International Airlines Flight 752 shortly after its takeoff from Tehran on Tuesday night, causing the plane to crash and killing all 176 people on board.

Iranian Revolutionary Guard commander Gen. Amir Ali Hajizadeh on Saturday said the plane was downed due to "human error" and that his unit accepts "full responsibility" for the mistake.

Iran initially denied having anything to do with the crash, but US officials said early on that the plane had been shot down by the Iranian Revolutionary Guard Corps.