A Russian spy ship loitering in international waters off Kauai for several days has delayed a Missile Defense Agency missile test, officials said Wednesday.

U.S. Pacific Fleet at Pearl Harbor said in a statement that it “is aware of the Russian vessel operating in international waters in the vicinity of Hawaii, and will continue to track it through the duration of its time here. Through maritime patrol aircraft, surface ships and joint capabilities, we can closely monitor all vessels in the Indo-Pacific area of operations.”

The planned test could be for an SM-6 missile intercept of a replicated cruise or ballistic missile threat. An official said the test was delayed because the United States did not want the Russian vessel to “collect on” the effort.

The Honolulu Star-Advertiser contacted the Missile Defense Agency on Wednesday and asked about the impact of the Russian presence on the missile test, but the agency chose not to comment.

U.S. Naval Institute News, which was the first to report the presence of the ship, said it is the Russian Navy Vishnya-class auxiliary general intelligence, or AGI, ship Kareliya (SSV-535).

The Vladivostok-based ship is one of seven AGIs specializing in signals intelligence, USNI News said.

The website navyrecognition.com reported in 2017 that the Kareliya had been mothballed for more than 10 years until January 2014 when a “comprehensive repair and retrofit of the ship” was performed. After that, it was turned over to the Russian Pacific Fleet.

USNI News said the Russian ship was operating 13 nautical miles west of Kauai in international waters. Territorial waters begin at 12 nautical miles.

An official said the appearance of Russian or Chinese intelligence-gathering vessels off Hawaii is within historical norms with no signs of a surge.

In 2018 after China was disinvited from the prestigious Rim of the Pacific exercise, it made an appearance anyway — dispatching a spy ship to international waters off Hawaii.

Chilean Commodore Pablo Niemann, the combined forces maritime component commander for that year’s RIMPAC, said at the time that, “it is very disappointing that the presence of a non-participating ship could disrupt the exercise. I hope and expect all seafarers to act professionally so we may continue to focus on the work at hand and building on the spirit of cooperation that gives purpose to this exercise.”

The People’s Liberation Army Navy AGI ship was detected off Hawaii coinciding with the early phase of the at-sea portion of what is the world’s largest international maritime exercise.

In 2014, the first time China was invited to participate in RIMPAC, it also sent a spy ship. The Navy had previously confirmed that China sent a surveillance ship near Hawaii in 2012 as well. Russia is seen as being more likely to send spy ships off Hawaii than China.

In 2016 during RIMPAC, a Russian Balzam-class AGI ship arrived in international waters off Hawaii. The exercise is held every two years.

Retired Navy Capt. Carl Schuster, a former director of operations at U.S. Pacific Command’s Joint Intelligence Center and an adjunct professor at Hawaii Pacific University, said at the time of the 2018 Chinese AGI arrival that the presence was more than a poke in the eye to the United States.

“It’s actually intelligence-gathering,” Schuster said, adding “it’s something that any prudent country would do, although it always has a political element to it.”

“But an AGI is looking at how we do tactics, how we do procedures, they are also monitoring all the radar signals,” Schuster said of the RIMPAC monitoring.

Twenty-five nations, 46 surface ships, five submarines, 18 national land forces, more than 200 aircraft and 25,000 personnel were gathered mainly in Hawaii but also in Southern California for that year’s RIMPAC.

Schuster called it an “intelligence opportunity that’s hard to turn down.”