0829 GMT January 29, 2020
The vessel was 70 miles off the coast of Delaware on Tuesday, heading north at 10 knots, an official told Fox News on condition of anonymity.
The US territorial sea extends 12 nautical miles from the baseline, and that means the Russian ship was patrolling in international waters, the network said.
The destination of the ship was not immediately known.
The ship, the SSV-175 Viktor Leonov, last sailed near the US in April 2015, an official said.
The Leonov, which is outfitted with high-tech electronic spying gear, is capable of intercepting signals, known as SIGINT, as well as measuring US Navy sonar capability, another official said.
Theship is also armed with surface-to-air missiles.
“It’s not a huge concern, but we are keeping our eyes on it,” one official said.
In the past, Russian surveillance ships have sailed off the coast of Kings Bay, Georgia, which is home to the US Navy Fleet ballistic missile submarines armed with Trident missile nuclear weapons.
In September 2015, another Russian intelligence-gathering ship was seen operating outside the submarine base in Kings Bay.
Around the same time, a senior Pentagon official acknowledged that American “oceanographic ships” operating in waters off the coast of Russia, were actually gathering intelligence on the country.
There have been several close encounters between Russian jets and US warships patrolling near Russian territorial waters.