Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

A Russian intelligence ship has been spotted off the coast of Groton, Connecticut, where Naval Submarine Base New London is located, U.S. defense officials said.

The ship, approximately 30 miles from the U.S. naval base, is still in international waters. The boundary for the ship to remain in international waters is 12 nautical miles, according to the U.N. Convention on the Law of the Sea.

"We are aware of the vessel's presence," Lt. Col. Valerie Henderson, a spokeswoman for the Defense Department, told NBC News in an email. "It has not entered U.S. territorial waters. We respect freedom of navigation exercised by all nations beyond the territorial sea of a coastal State consistent with international law."

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

The ship, the Viktor Leonov, is expected to sail down the east coast and head to the Caribbean, according to Fox News. The White House has not commented on the presence of the ship.

Related: Trump Blames Russian Connection ‘Conspiracy Theories’ on Clinton Campaign ‘Cover Up’

Although the Russian vessel hasn’t broken any international laws with its presence, several Connecticut lawmakers have expressed concern over its proximity in light of the 2016 election hacks and outstanding questions surrounding Trump's former national security adviser's communications with Russia.

Rep. Joe Courtney, D-Connecticut, who serves on the Armed Services Committee and is the ranking member of the Seapower and Projection Forces Subcommittee, called it an "unacceptable, aggressive action."

"A Russian spy ship patrolling 30 miles from the Groton SUBASE underscores that the threats posed by a resurgent Russia are real," Courtney said in a press release.

On Wednesday, Sen. Chris Murphy, D-Connecticut, tweeted that Russia "is acting like it has a permission slip to expand influence" and "test limits" by placing a ship so close to the United States.

Russia is acting like it has a permission slip to expand influence, test limits of reach. Questions are obvious: does it, and if so, why? https://t.co/6Hsm7T2GO2 — Chris Murphy (@ChrisMurphyCT) February 15, 2017

"While this is not wholly unprecedented, it’s part of a series of aggressive actions by Russia that threaten U.S. national security and the security of our allies," Murphy, the ranking Democrat on the Foreign Relations Subcommittee on Europe and Regional Security Cooperation, said in a statement.

Republican members of the Homeland Security and Governmental Affairs Committee, which has primary oversight of the Homeland Security Department, did not immediately respond to a requests for comment. Sen. Rand Paul, R-Kentucky, who is on the committee, declined to comment.

Related: Michael Flynn: A Timeline of His Rise and Fall and the Russia Call

Murphy asserted that the move was disconcerting as it came just a one day after it was reported that Russia secretly deployed a cruise missile in what officials have called a violation of a Cold War-era treaty and not long after Russian aircraft buzzed a U.S. destroyer in the Black Sea.

"President Trump and his administration must end their silence and immediately respond to these threats to our national security," Murphy said.