After an American MQ-9 Reaper drone was forced to crash land in the Black Sea on Tuesday following an incident with a Russian fighter jet, the Pentagon has released video footage from onboard the drone.
US officials say it shows a Russian SU-27 fighter jet 'fuel dumping' close by before a second jet flies in and collides with the drone's propeller.
Moscow has disputed this, saying the drone caused its own failure.
So, what do we know about the incident so far?
Where was the drone and what was it doing?
The Pentagon said the incident happened as the drone conducted a routine flight in international airspace over the busy waterways of the Black Sea.
America has said the crash would not stop it carrying out surveillance flights in the area.
What has the US said happened?
US officials said two Russian SU-27 Flankers intercepted the drone and shadowed it for 40 minutes.
The Reaper was sprayed with jet fuel – 'fuel dumping' is a tactic used to reduce the aircraft's weight in order for it to be able to land quickly.
The drone propellor was then struck by a Russian jet which caused the unmanned aerial vehicle to ditch into the sea.
What is Russia's account?
Russia's Defence Ministry said it scrambled the Su-27s after the Reaper flew into a prohibited area.
Moscow said the drone then made a sharp manoeuvre and lost guidance before crashing into the sea.
The Russian Ambassador to the United States, Anatoly Antonov, clarified: "There was no contact; no weapons were used by our fighter jets."
Both jets landed safely.
What does a defence analyst think?
Defence analyst Professor Michael Clarke, former director general of the defence and security think tank Royal United Services Institute (RUSI), told Forces News: "The pilot is very lucky to be alive and, almost certainly, I'm 99% certain, that this was a flying accident caused by pilot error.
"It's impossible to believe that a Su-27 pilot could deliberately just fly into, damage a propeller, on something that was only going a maximum of 250mph, when his stalling speed is probably higher than that."
Prof Clarke added: "The pilot who could do that deliberately hasn't yet been born. This was an accident."
Recovery of the drone
The race is now on to retrieve the drone wreckage and the US will be keen to avoid a repeat of 2019 when Iran showed off the wreckage of an American Global Hawk drone shot down over the Strait of Hormuz.
Russia has said it will attempt to retrieve the wreckage, which may have sunk to depths of up to 5,000 feet (1,500m) below the surface.
Nikolai Patrushev, the secretary of Russia's National Security Council, said on state TV: "I don't know whether we'll be able to retrieve it or not but it has to be done," adding "we'll certainly work on it. I hope, of course, successfully."
General Mark Milley, Chairman of the US Joint Chiefs of Staff, said that "mitigating measures" were taken to prevent any sensitive data from falling into Russia's hands.
With US warships unable to access the Black Sea, Washington may have to use the services of its allies to attempt a recovery.
Prof Clarke says the significance of the downed Reaper will be what "it was carrying".
He added: "The electronic surveillance material, whatever it was, used on that particular Reaper, that would be quite important."
"I'm not surprised there's quite a big effort by the United States to retrieve the debris or even the whole airframe."