Russian jets buzzed a U.S. guided missile destroyer in the Black Sea last week, the first such known incident since President Trump took office.
U.S. European Command confirmed the incident Tuesday.
The incident “was deemed unsafe and unprofessional because of various factors including low altitude and high speed,” said Lt. Col. David Faggard, a command spokesman.
The fly-by happened Friday and involved the USS Porter, which was in the Black Sea to participate in the Romanian-led multinational Sea Shield exercises.
The exercise had wrapped up when the Porter was buzzed by a Russian IL-38 transport aircraft flying at an “unusually low” altitude, Faggard said. After that, two Russian Su-24 jets flew by at a low altitude and a high speed. Finally, a different Su-24 buzzed the ship, he said.
The Porter was in international waters at the time, he added.
The U.S. military is reviewing the planes' action to see whether it violates the 1972 Incidents at Sea agreement between the United States and Russia, and will respond from there, Faggard added.
This was the first such encounter between the U.S. and Russian militaries in the European Command area in 2017, he said.
The incident was first reported Tuesday afternoon by The Washington Free Beacon.
Russian aircraft repeatedly buzzed U.S. jets and ships throughout 2016. Most recently, in September, a Russian fighter jet came within 10 feet of a Navy surveillance plane in international airspace over the Black Sea.
Before that, in June, the United States and Russia traded accusations over who was to blame for ships from each country getting dangerously close to each other in the Mediterranean Sea.
That followed Russian aircraft repeatedly buzzing the USS Donald Cook in the Baltic Sea and a Russian aircraft barrel-rolling over a U.S. reconnaissance plane in international airspace over the same area, both in April.
Also, in January 2016, a Russian fighter jet flew within 15 feet of a U.S. reconnaissance plane over the Black Sea.
The latest fly-by comes as Trump is facing increasing pressure over his desire to improve relations with Russia. His national security advisor, Michael Flynn, resigned late Monday amid reports that he communicated with the Russian ambassador to the U.S. about sanctions prior to Trump's inauguration and misled top White House officials about it.
Also Tuesday, The New York Times reported that Moscow violated an arms treaty with the United States by deploying a cruise missile inside Russia.