U.S. officials are tracking a Russian spy ship that cruised up the East Coast to within 30 miles of the U.S. Naval Submarine Base in Groton Wednesday, Courant reports.

Some lawmakers called the move another aggressive action from Russian President Vladimir Putin.

“A Russian spy ship patrolling 30 miles from the Groton sub base underscores that the threats posed by a resurgent Russia are real,” U.S. Rep. Joe Courtney, D-2nd District, said in a written statement.

Two retired U.S. Naval submarine commanders downplayed the significance of Russia’s presence, saying the ship presents little threat to U.S. security. Russian intelligence ships routinely patrol areas outside U.S. naval bases and track U.S. and allied forces naval exercises.

“The U.S. Coast Guard is aware of a Russian Federation-flagged vessel transiting international waters off the East coast of the United States, as we are of all vessels approaching the U.S. The ship has not entered U.S. territorial waters, which extend 12 miles out to sea,” the Coast Guard said in a statement. “We respect freedom of navigation exercised by all nations beyond the territorial sea of a coastal state consistent with international law. The Coast Guard continues to coordinate with federal agency partners to monitor maritime contacts operating in the vicinity of U.S. shores.”

While the U.S. Coast Guard is tracking the ship’s course, it would not disclose its location.