Claims of a collision between a Russian fighter jet and a US surveillance drone over the Black Sea have triggered diplomatic protests in the US.
US and Russian officials have conflicting accounts of what happened between the MQ-9 Reaper drone and the Russian Su-27 fighter jet, with each blaming the other.
Here's what we know about the incident.
Here's what the Pentagon says
The drone was conducting a routine surveillance mission over the Black Sea in international airspace.
According to the Pentagon and the US European Command, two Russian Su-27 aircraft dumped fuel on the MQ-9.
US authorities say the Russian jets flew around and in front of the drone several times for between 30 and 40 minutes, and then one of the Russian aircraft "struck the propeller of the MQ-9, causing US forces to have to bring the MQ-9 down in international waters".
US Air Force General James Hecker says the Russian jet's actions "nearly caused both aircraft to crash".
It's not clear if the contact was accidental or intentional. However, the US says the Russian aircraft were trying to intercept the drone.
Here's what the Russian Defence Ministry says
The Russian Defence Ministry says the US drone was flying near the Russian border and intruded into an area declared off-limits by Russian authorities.
It says the Russian military scrambled fighters to intercept the US drone, claiming, "as a result of sharp manoeuvre, the US drone went into uncontrollable flight with a loss of altitude and collided with water surface".
Ever since the 2014 annexation of Crimea and long before Russia invaded Ukraine last year, Moscow has charged that US surveillance planes were flying too close to its borders while ignoring the notices issued by Russia.
Nations routinely operate in international airspace and waters, and no country can claim limits on territory outside of its own border.
The ministry said the Russian aircraft scrambled to intercept the drone but didn't use weapons on it nor impact it.
Then came a conflict of words
Following the conflicting reports, a Pentagon spokesman raised the possibility that the US Defense Department could eventually declassify and release footage it has of the collision.
State Department spokesman Ned Price called it a "brazen violation of international law".
And White House National Security spokesman John Kirby says the US will be "expressing our concerns over this unsafe and unprofessional intercept".
Russian ambassador to the United States Anatoly Antonov was summoned to a meeting with US officials.
"We view this incident as a provocation," Russia's RIA state news agency reported Mr Antonov as saying.
"As for us, we do not want any confrontation between the United States and Russia. We are in favour of building pragmatic relations for the benefit of the Russian and American peoples."
Will the drone be recovered?
The drone would likely be difficult to recover, due to the depth of the water in the area, US Chairman of the Joint Chiefs of Staff General Mark Milley says.
"It probably sank to some significant depths, so any recovery operation from a technical standpoint would be very difficult," General Milley says.
He cautioned that it would take several days before the United States would know for certain the size of the debris field in waters as deep as 1,200 to 1,500 meters.
Russia says it will try to retrieve the remains but appeared to acknowledge the challenges.
"I don't know whether we will be able to retrieve it or not, but that it has to be done. And we'll certainly work on it. I hope, of course, successfully," Kremlin Security Council Secretary Nikolai Patrushev says.
General Milley says the United States had already taken measures to guard against a loss of sensitive intelligence if the drone were to be recovered by Russia.
"We're quite confident that whatever was of value is no longer of value," General Milley said.
What is a MQ-9 Reaper?
The MQ-9 Reaper is a large, unmanned Air Force aircraft made by General Atomics that is remotely operated by a two-person team. It includes a ground control station and satellite equipment and has a 20-metre wingspan.
Its ground team includes a rated pilot, who is responsible for flying the aircraft, and an enlisted aircrew member, who is charged with operating the sensors and guiding weapons.
The Reaper was first flown in 2001 and was used routinely during the Iraq and Afghanistan wars for surveillance and air strikes. The Reaper can be either armed or unarmed.
It can carry up to eight laser-guided missiles, including Hellfire missiles and other sophisticated munitions, and can loiter over targets for about 24 hours.
Each Reaper costs about $US32 million ($47.9 million) and can fly at speeds of up to 445 kilometres per hour and altitudes of up to 50,000 feet and has a range of about 2,600 kilometres.
UNSW Associate Professor Michael Richardson — who examines the intersections of war and technology — described the Reaper as "basically a huge glider with a fancy lawn mower motor strapped to the middle".
Have there been incidents before?
In 2016, a Reaper drone crashed in Syria's north during a mission against ISIS, the US Air Force says.
In 2019, it was reported that the Iran-aligned Houthi group had taken responsibility for using a surface-to-air missile to reportedly shoot down a US MQ-9 Reaper drone over Yemen.
At the time, a US official said losing an expensive drone like that was not unprecedented and it was not likely to provoke a major response from Washington.
The Pentagon publicly condemned Russian authorities in 2020 after Russian jets crossed in front of a B-52 bomber that was flying over the Black Sea, and flew as close as 100 feet in front of the bomber’s nose, causing turbulence.
Russian jets have also buzzed US warships during exercises in the Black Sea. In 2021, Russian warplanes buzzed the USS Donald Cook, a navy destroyer, which had been taking part in a major exercise.
AP/Reuters
