A Russian anti-submarine destroyer chased off a U.S. submarine near the Kuril Islands, forcing it to leave the country's territorial waters, Moscow said Saturday, amid raging tensions over Ukraine.
A Pentagon spokesman, asked by AFP for comment, said only: "We are aware of press reporting about an alleged naval incident in the Pacific. We cannot confirm the details of these reports at this time."
A senior administration official said Saturday they had no additional information about the alleged incident.
The Russian defense ministry said that during planned military drills the Marshal Shaposhnikov destroyer detected a U.S. Navy Virginia-class submarine in Russian territorial waters near the Kuril Islands in the northern Pacific.
When the submarine ignored demands to surface, the crew of the frigate "used appropriate means" and the U.S. submarine left at full speed, the ministry said, without providing further details.
The ministry also said it had summoned the U.S. defense attaché in Moscow over the incident.
"In connection with the violation by the U.S. Navy submarine of the state border of the Russian Federation, the defense attaché at the U.S. embassy in Moscow was summoned to the Russian defense ministry," the defense ministry said.
The Kurils, which lie north of Japan's Hokkaido island, have been controlled by Moscow since they were seized by Soviet troops in the waning days of World War II. The incident took place near the Kuril island of Urup.
It came amid soaring tensions between Russia and the West that have seen Moscow surround Ukraine on three sides with more than 100,000 troops, with Washington warning that an all-out invasion could begin "any day."
Russian President Vladimir Putin on Saturday condemned the claims as a "provocation."
U.S. President Joe Biden warned Putin Saturday that the United States will "respond decisively and impose swift and severe costs" should Russia invade Ukraine. The warning comes as U.S. officials say a Russian invasion could begin "at any time."
With an escalated Russian military buildup on the borders of Ukraine, Mr. Biden emphasized on a phone call with Putin that an invasion "would produce widespread human suffering and diminish Russia's standing."
The U.S. State Department has ordered non-emergency employees to leave the U.S. embassy in Kyiv, Ukraine.