A Russian fighter jet forced down a US Air Force drone over the Black Sea on Tuesday.

Here's what to know:

US-Russia drone intervention: A Russian jet downed a US drone over the Black Sea. Aircraft from both countries have operated over the Black Sea during the course of the war, but this is the first known such interaction, a potentially dangerous escalation at a critical time in the fighting. The incident prompted US officials to express "strong objections" to diplomats. Pentagon Press Secretary Brig. Gen. Pat Ryder called it "uncommon and unfortunate and unsafe." President Joe Biden and US allies have been briefed, according to the White House and the Pentagon.

Russian response: Moscow has pushed back, denying that its fighter jets came "into contact" with the US drone. Russian Ambassador to the US Anatoly Antonov said Russia does not want a "confrontation" with the US, but the craft was too close to the Russian border. The drone has not been recovered, a spokesperson for US European Command said.