The Russian Ministry of Defense stated that one of its ships on Tuesday intercepted a U.S. Navy destroyer in its sovereign waters and successfully drove it out with a threat to ram the intruding vessel.

The U.S. Navy denies this account, asserting its ship was not in Russian waters and had not been “expelled” from them, Voice of America (VOA) reported.

Moscow claimed it found the USS John S. McCain 1.2 miles inside its maritime territory in Peter the Great Bay, an inlet on the Sea of Japan which surrounds the Russian port of Vladivostok, near the border with North Korea, according to the BBC.

The Russian Pacific Fleet’s Admiral Vinogradov, a destroyer-class warship, reportedly hailed the McCain and warned its crew of “the possibility of using ramming to get the intruder out of the territorial waters,” the Defense Ministry said.

Russia claims Peter the Great Bay as its maritime territory, as did the Soviet Union beginning in 1984. The U.S. disputes this claim, asserting the bay is an international zone. The coastline that marks the bay, however, has been in Russian hands since the 1860 Treaty of Peking in which China surrendered portions of Manchuria to the Russian Empire under Tsar Alexander II. Prior to that, the Qing Dynasty controlled the territory.

The U.S. Navy denied the Russian statement, emphasizing that the destroyer was not in Russian waters.

“The Russian Federation’s statement about this mission is false. USS John S. McCain was not ‘expelled’ from any nation’s territory,” the Navy stated on Tuesday.

The McCain was reportedly engaged in a freedom of navigation operation, sailing through the disputed waters to support international use of the area. U.S. Navy ships regularly make such voyages in disputed Pacific waters, especially those the Chinese claim, though it hadn’t entered Peter the Great Bay since 2018 and, prior to that, since 1987.

Russia’s Far East has been a point of tension this year. Russian President Vladimir Putin’s removal of Gov. Sergei Furgal prompted sustained domestic unrest and a subsequent troop buildup in the border region.

On the naval front, Putin announced in July that the naval warships would receive a substantial upgrade in the form of hypersonic nuclear strike weapons as part of a larger effort to overhaul Russia’s Navy and secure its claims.

Russia announced in November that it would construct a full-scale base near Port Sudan capable of housing nuclear ships, which would allow Russia to field a competing fleet in the Indian Ocean to counter maritime activities of the American and Chinese Navies.