The Russian Defence Ministry has handed a note to the US military attache following the US submarine violating Russian territorial waters.
"On February 12, a representative of the US embassy's military attache office for defence issues was handed over a note at the Russian defence ministry's main directorate of international military cooperation in Moscow in relation to the violation of Russia's state border by a US navy submarine," the ministry told journalists.
According to the ministry, the sub's provocative behaviour posed a threat to Russia's security. The US must prevent such incidents in the future, Moscow said. Russia reserves the right to use any means to ensure security in its territorial waters, the country's defence ministry added.
Earlier on Saturday, Russia said a US submarine was discovered at 10:40 Moscow time near one of the Kuril Islands of Urup. The Virginia-class submarine entered an area where the Russian Pacific Fleet was conducting its scheduled exercises.
According to the ministry, the submarine was addressed both in Russian and English and was urged to immediately come up to the surface – but the warning was ignored. Then, in line with the guidance about the underwater protection of the borders, the crew of the Russian "Marshall Shaposhnikov" frigate used "relevant methods." The submarine left the area quickly, the ministry added.
The incident comes as tensions threaten to boil over between Moscow and NATO over European security and Western speculation about Russia's alleged plans to invade Ukraine. Moscow has repeatedly said that it does not plan to attack any country and stressed that the West's persistence in hyping the "Russian threat" rhetoric only hampers diplomatic efforts to avoid further escalation.