Defense Secretary Lloyd Austin spoke to his Russian counterpart on Wednesday about the destruction of a U.S. drone over the Black Sea after an encounter with Russian fighter jets, which brought the two countries closest to direct conflict since Moscow’s invasion of Ukraine a year ago.

It was the first call between Austin and Defense Minister Sergei Shoigu since October. And Gen. Mark Milley, chairman of the Joint Chiefs of Staff, had a similar call with his Russian counterpart, Gen. Valery Gerasimov, the chief of the General Staff of the Russian armed forces.

“We take any potential for escalation very seriously. And that’s why I believe it’s important to keep the lines of communication open,” Austin said at a Pentagon press briefing. “I think it’s really key that we’re able to pick up the phone and engage each other. And I think that that will help to prevent miscalculation going forward.”

The U.S. military said it ditched the Air Force MQ-9 Reaper in the sea after a Russian fighter jet poured fuel on the surveillance drone and then struck its propeller while it was flying in international airspace. Russia has denied that it caused the accident. The U.S. has said it was working on declassifying surveillance footage from the drone that would show Tuesday’s crash.

That the top U.S. and Russian defense and military leaders were talking so soon after the incident underscored the seriousness of the encounter over the Black Sea and that both sides recognized the need to tamp down the risks of escalation. Since Russia’s invasion of Ukraine, contact between U.S. and Russian military leaders has been limited, with Russian officials refusing to take U.S. military calls in the early months of the war.

There are still questions as to whether Russia meant to down the drone, even though the moments that led up to its crash were “intentional,” said Milley, who stood alongside Austin at the briefing.