A Russian warship caught a U.S. Navy destroyer operating in Russia's Pacific waters on Tuesday and chased it off, the Defense Ministry in Moscow said.
The USS John S. McCain, a guided-missile destroyer, violated Russia's territorial waters by moving two kilometers beyond the maritime border at 03:17 GMT into Peter the Great Gulf, the ministry said in a statement.
The U.S. ship had been operating for several days in the Sea of Japan and was being tracked by Russia, the ministry said.
The Admiral Vinogradov, an anti-submarine destroyer in Russia's Pacific Fleet, sent a warning to the U.S. ship and threatened to "use a ramming maneuver to drive the intruder out of its territorial waters."
The U.S. ship immediately returned to neutral waters, the statement said, and was being monitored.
The U.S. Pacific Fleet said in a statement that the USS John S. McCain had "asserted navigational rights" in the area "by challenging Russia's excessive maritime claims."
It gave no details of the incident but said the U.S. ship had been operating in the vicinity of the Peter the Great Gulf in an area the U.S. does not recognize as Russian territorial waters.
The area has been in dispute since 1984, when the Soviet Union declared it part of its waters, a claim that Russia has maintained.
Such incidents at sea are uncommon and a sign of continued post-Cold War tensions between Russia and the United States.
Last year the two countries traded accusations of dangerous maneuvers after the Admiral Vinogradov came close to a collision with the USS Chancellorsville in the East China Sea.