The U.S. military surveillance drone that crashed into the Black Sea may never be recovered, White House spokesman John Kirby said on Wednesday after the craft was intercepted by Russian fighter jets, worsening taut relations between Washington and Moscow.
However, Moscow says it will work to retrieve the wreckage.
"I don't know whether we'll be able to retrieve it or not but it has to be done. And we will certainly work on it," Russian Security Council secretary Nikolai Patrushev said in televised remarks.
"It has not been recovered," Kirby said in an interview with CNN. "And I'm not sure that we're going to be able to recover it. Where it fell into the Black Sea - very, very deep water. So we're still assessing whether there can be any kind of recovery effort. There may not be."
"That said, it's our property," Kirby added, and U.S. authorities will continue to explore recovery options.
If the Russians collect the wreckage, U.S. authorities have taken precautions to ensure that their ability to draw useful intelligence will be limited, Kirby told ABC, without elaborating on how that will be accomplished.
It is believed that such aircraft have self-destruct explosives that the operator can detonate, shattering the UAV and its sensitive equipment into fragments. However, this has not been officially confirmed.
The State Department on Tuesday summoned Russia's ambassador to the United States, Anatoly Antonov, to express U.S. concerns over the encounter.
"The message that we delivered to the Russian ambassador is that they need to be more careful in flying in international airspace near U.S. assets that are, again, flying in completely legal ways, conducting missions in support of our national security interests," Kirby said on CNN. "They're the ones that need to be more careful.
"The message was: Don't do this again," Kirby added later on ABC.
Antonov after the meeting said that the drone "deliberately and provocatively was moving toward Russian territory with transponders turned off."
American officials have stressed that the United States would continue to fly over international waters in the area.
"And it is incumbent upon Russia to operate its military aircraft in a safe and professional manner," U.S. Defense Secretary Lloyd Austin said on Wednesday at the start of a virtual monthly meeting with allies on arming Ukraine.