Earlier this week, a Russian fighter came within 20 feet of an American military reconnaissance aircraft flying in international airspace over the Black Sea.
The daylight encounter between the two aircraft was deemed to be "safe and professional" by the U.S. military and the Russian Defense Ministry described the Russian fighter as having approached the U.S. Navy P-8A Poseidon at "a safe distance."
"May 9, 2017, a Russian SU-27 came within approximately 20 feet of a U.S. Navy P-8A Poseidon while the U.S. Navy aircraft was conducting routine operations in international airspace," said Captain Pamela Kunze, a spokesperson for U.S. Naval Forces Europe. "The interaction lasted 65 minutes and was considered safe and professional by the P-8A's mission commander."
Kunze noted that U.S. Navy ships and aircraft operate routinely in the Black Sea consistent with international law, saying, "U.S. Navy aircraft and ships routinely interact with Russian units in international seas and water and most interactions are safe and professional."
According to a statement from the Russian Defense Ministry, the Russian fighter approached the American aircraft at "a safe distance" and identified it as a P-8A Poseidon.
"The Russian fighter performed a maneuver to greet the U.S. pilots, after which the U.S. reconnaissance plane changed its course and headed away from the Russian border," the ministry said.
The Ministry said that the encounter occurred at 12 p.m. Moscow time on May 9 and that the American aircraft had been detected "approaching the Russian state border" while over the Black Sea.
A U.S. official said the aircraft were 20 feet apart "wingtip to wingtip" for a few minutes, but noted that, despite the close distance, the encounter was professional and not unusual.
"Distance is only one of many variables considered when defining what is safe and professional," said Kunze.
"At sea, distance, sea state, visibility, size of the vessel, speed, how it maneuvers, and navigational hazards all impact whether an event is characterized as safe or unsafe, professional or not professional," he continued. "For aviation interactions, distance, speed, altitude, rate of closure, visibility and other factors impact whether an event is characterized as safe or unsafe, professional or not professional. Every event is unique and any single variable does not define an event. It is up to the commander of the vessel -- whether ship or aircraft -- to evaluate all of the variables and assess each interaction individually."
In the past, some Russian military aircraft have performed risky "barrel roll" maneuvers near American military aircraft flying in international airspace, which led the U.S. to label the interactions as "unsafe and unprofessional."
The U.S. official said that, in this incident, both aircraft visually identified each other and the Russian aircraft approached the American plane in a professional manner.
ABC News' Patrick Reevell and Anastasia Butler contributed to this report.