The United States has protested an intercept of a U.S. reconnaissance plane by a Russian fighter jet last week, calling it "unsafe and unprofessional."
Pentagon spokesman Mark Wright said on April 12 the United States was filing a complaint to Russia "through diplomatic channels" after the April 7 incident over the Baltic Sea.
Russian officials have denied their pilot did anything wrong, according to several news reports.
According to the Pentagon, the U.S. RC-135U plane was flying in international airspace north of Poland.
U.S. officials say a Russian SU-27 fighter came up behind the U.S. plane at high speed, and then made two more dangerously close passes.
It isn't the first time Washington has protested to Moscow what it considered to be an unsafe intercept.
In April 2014, a Russian fighter jet intercepted a U.S. reconnaissance plane in international airspace over the Sea of Okhotsk.