A Russian military aircraft engaged "in an unsafe interaction" with a U.S. Navy surveillance plane in international airspace, the U.S. State Department said.
The incident took place over the Black Sea on Monday, the State Department said.
The pilot of a Russian Su-27 fighter was "closing to within five feet and crossing directly in front of" the American EP-3 aircraft's flight path, department spokeswoman Heather Nauert said in a statement. That caused the American surveillance plane "to fly through the Su-27's jet wash," the U.S. 6th Fleet said. The intercept lasted two hours and 40 minutes, the Navy said.
The Russian defense ministry said the Su-27 returned to its base after the American plane changed its course, according to Reuters, citing the Russian news agency RIA.
"While the U.S. aircraft was operating under international law, the Russian side was flagrantly violating existing agreements and international law," Nauert said.
"This is but the latest example of Russian military activities disregarding international norms and agreements," it continued. "We call on Russia to cease these unsafe actions that increase the risk of miscalculation, danger to aircrew on both sides, and midair collisions."