Close Encounter Between Russian Fighter Jet and US Spy Plane

— -- A close encounter occurred between a Russian fighter jet and a U.S. military reconnaissance aircraft late last month in international airspace over the Black Sea, U.S. military officials confirmed to ABC News.

Pentagon Spokesman Col. Steve Warren today called it "an unsafe intercept" saying it was done in an "unprofessional and inappropriate" manner.

On May 30, two Russian Sukhoi Su-27 fighter jet conducted separate intercepts of a large U.S. RC-135 reconnaissance aircraft. According to Warren, the first of the two intercepts came dangerously close when the Russian pilot cam behind the American plane, passed underneath it and then passed it on the right hand side.

Warren said it was unclear if the jet was intentionally conducting a dangerous maneuver or if it was perhaps a general "lack of training" on behalf of the Russian pilot.

"The reason is concerns us is that these unsafe intercepts can lead to accidents and potentially tragedy or miscalculations of some sort and that is not what we want to see," Warren said.

The U.S. has filed a formal complaint with the Russians.

In April, there was a similar incident also involving a Russian fighter jet and a U.S. military reconnaissance aircraft over the Baltic Sea. The United States accused the Russian pilot of making multiple passes, at the time calling it "unsafe and unprofessional." Although the U.S. filed a formal protest, the Russians denied any wrongdoing.

Earlier this month, the Pentagon released video of a Russian fighter making a low-level pass at a U.S. Navy destroyer, also in the Black Sea.