U.S. Northern Command and the Coast Guard have been tracking a Russian spy ship equipped with electronic surveillance gear that has been lurking off the East Coast of the United States.

On Monday, the Coast Guard sent out a Maritime Safety Information Bulletin warning boaters of reports of the Viktor Leonov operating in an “unsafe manner” off the coast of South Carolina and Georgia.

On Tuesday, the Coast Guard said the Russian ship was operating in USCG’s Jacksonville, Florida, area of responsibility, which encompasses roughly 40,000 square miles of ocean and nearly 190 miles of coast from Kings Bay, Georgia, to Port Malabar, Florida.

“This unsafe operation includes not energizing running lights while in reduced visibility conditions, not responding to hails by commercial vessels attempting to coordinate safe passage and other erratic movements,” the Coast Guard posted on its bulletin.

“Vessels transiting these waters should maintain a sharp lookout and use extreme caution when navigating in proximity to this vessel. Mariners should make reports of any unsafe situations to the United States Coast Guard,” the Coast Guard said in its safety message.

Adm. James Foggo III, the commander of U.S. Naval Forces Europe and U.S. Naval Forces Africa, told reporters Dec. 18 that the Russian spy ship was operating a “couple hundred” miles off the East Coast.

North American Aerospace Defense Command and U.S. Northern Command told Military Times that they were tracking the Russian ship.

“We are aware of Russia’s naval activities, including the deployment of these intelligence collection ships in the region,” Maj. Mark R. Lazane, a spokesman with NORTHCOM, told Military Times in an emailed statement.

“While we won’t discuss specific measures being taken, NORAD and NORTHCOM routinely conduct air and maritime operations to ensure the defense of the United States and Canada,” Lazane said.