A Russian surveillance ship has been behaving in an “unsafe manner” off the coast of the southeastern United States, the U.S. Coast Guard said. The U.S. Coast Guard in Charleston, South Carolina, issued a maritime safety information bulletin about the ship, the Viktor Leonov, on Sunday. “The United States Coast Guard has received reports indicating that the RFN Viktor Leonov (AGI-175) has been operating in an unsafe manner off the coast of South Carolina and Georgia,” the notice said. The ship’s operation has been deemed unsafe because it is not using running lights in low visibility weather and has been unresponsive to commercial vessels attempting to establish its position to avoid potential collisions, along with other “erratic behaviors,” a U.S. official close to the matter told CNN. The U.S. Navy’s USS Mahan is operating close to the Russian ship, CNN reports. The Viktor Leonov has been regularly patrolling in international waters along the eastern coast of the U.S. since 2015, as well as in the Caribbean.