(CNN)A Russian submarine being tracked by a British naval warship on patrol in the North Atlantic more than a year ago hit a sonar the ship was towing, according to the UK Ministry of Defence.
Russian submarine collided with British warship part in rare event
"In late 2020 a Russian submarine being tracked by HMS Northumberland came into contact with her towed array sonar," a UK Ministry of Defence spokesperson said in a statement Thursday.
"The Royal Navy regularly tracks foreign ships and submarines in order to ensure the defence of the United Kingdom," the statement said.
A towed array sonar is a sensor spooled out by a ship when it is deployed.
According to the British Royal Navy, the HMS Northumberland carried out a "vital mission to protect UK waters and the nation's nuclear deterrent" in 2020.