The U.S. Coast Guard has begun broadcasting a “Marine Safety Information Bulletin” to alert mariners of the presence and unusual behavior of a Russian surveillance ship named “Viktor Leonov” sailing off of America’s southeastern coast.

The Vishnya-class spy ship has been traversing the international waters just off of America’s Southeast coast for the better part of a week now, currently sailing south past the Carolinas and Georgia, toward Florida. As long as the vessel doesn’t come closer than 12 nautical miles to America’s coastline, what it is doing is perfectly legal — but its questionable behavior has now prompted U.S. officials to accuse its captain of operating the ship in an “unsafe manner.”

According to reports, the Viktor Leonov has been maneuvering without its running lights turned on, even during low visibility weather conditions. The ship has also refused to answer hails from nearby commercial vessels attempting to safely traverse the waters just beyond America’s coastline. These communications are meant to establish the positions of vessels in the area with the intention of avoiding mid-sea collisions. Other reports have accused the vessel of executing “erratic maneuvers,” adding to the risk of collision with other nearby vessels.

It’s not at all uncommon for Russian surveillance vessels to operate just outside of America’s territorial waters. In fact, the Viktor Leonov has been conducting these sorts of voyages at regular intervals since 2015. It is, however, less common for these vessels to blatantly disregard international norms regarding safety.

The U.S. Coast Guard isn’t alone in keeping tabs on the spy ship’s unusual behavior. U.S. Northern Command also keeps a watchful eye on the behavior of foreign military vessels operating in and around America’s territorial waters.

“We are aware of Russia’s naval activities, including the deployment of intelligence collection ships in the region,” Navy spokesperson Capt. Pamela Kunze said. “While we won’t discuss specific measures being taken, NORAD and USNORTHCOM routinely conduct air and maritime operations to ensure the defense of the United States and Canada.”

The U.S. Navy operates a number of installations along the Eastern Seaboard, which are likely the targets of Russian surveillance, but have also been used for high-stakes training exercises in the past. Russia announced last year that it had maneuvered an undisclosed number of nuclear attack submarines into position just outside American naval installations along the East Coast, and that the subs returned to Russian waters undetected. Whether or not they truly were undetected remains subject to debate, but the United States re-established its 2nd Fleet shortly thereafter with the renewed purpose of protecting America’s Atlantic coastline.