The U.S. Coast Guard revealed on Thursday that a Russian military intelligence ship was detected operating close to U.S. territorial waters on October 29. The Coast Guard continues to keep a close watch on this vessel.

Authorities noted that the Vishnya-class spy ship was located approximately 15 nautical miles off the coast of Oahu. This prompted a response from the Coast Guard, which dispatched an HC-130 Hercules aircraft from Air Station Barbers Point as well as the Coast Guard Cutter William Hart to the area.

Responding to the Russian vessel, identified as the Kareliya, an Auxiliary General Intelligence ship of the Russian Federation Navy, the Coast Guard carried out a secure and professional overflight and navigated near the ship, as stated in a press release.

On Thursday, November 13, the U.S. Coast Guard addressed the presence of the Russian military vessel off the coast of Honolulu, Hawaii.

Complying with international law, the Coast Guard assured that its personnel are closely monitoring the ship’s activities to ensure maritime security for U.S. vessels operating in the vicinity of U.S. territorial waters.

Coast guardsmen will also monitor the vessel to support U.S. homeland defense efforts.

“The U.S. Coast Guard routinely monitors maritime activity around the Hawaiian Islands and throughout the Pacific to ensure the safety and security of U.S. waters,” Capt. Matthew Chong, chief of response for the Coast Guard Oceania District, wrote in a statement. 

The Coast Guard said it is continuing to monitor the ship, which was first spotted in October. (USCG)

“Working in concert with partners and allies, our crews monitor and respond to foreign military vessel activity near our territorial waters to protect our maritime borders and defend our sovereign interests.”

The Vishnya-class is a group of intelligence collection ships built for the Soviet Navy in the 1980s, according to the U.S. Army website. There are seven ships still in service with the Russian Navy. 

They are large, purpose-built vessels designed for signals intelligence gathering via an extensive array of sensors, according to the site. Data can be transmitted to shore via satellite link antennas.

While the ships are designed for intelligence gathering, they are armed with two AK-630 close-in weapon systems and SA-N-8 surface-to-air missile (SAM) launchers, for last resort self-defense, according to the Army.

The Russian ship is off the coast of Oahu, Hawaii, according to officials. (Julia Beverly/Getty Images)

Coast Guard Oceania District works in conjunction with U.S. Indo-Pacific Command and interagency partners to constantly monitor the activity of foreign military vessels operating near U.S. territorial waters to ensure homeland security and defense.

Under customary international law, foreign military vessels are permitted to transit and operate outside other nations’ territorial seas, which extend up to 12 nautical miles from shore.

The Coast Guard did not immediately respond to Fox News Digital’s request for comment.