A Russian naval and air exercise off Hawaii that Moscow said was its largest drills in the Pacific since the end of the Cold War and involved surface ships, anti-submarine aircraft and long-range bombers, has ended, but a Russian spy ship remains in the Hawaii operating area, according to a variety of sources.

The Russian government put out a release announcing the end of the drills that were generally several hundred miles west of Hawaii.

“The Russian vessels are transiting west and are out of the Hawaii Operation Area,” said Navy Capt. Mike Kafka, a spokesman for U.S. Indo-Pacific Command at Camp H.M. Smith. “As part of our normal daily operations, we continue to track all vessels in the Indo-Pacific area of operations through maritime patrol aircraft, surface ship and joint capabilities.”

Kafka said the Russian vessels operated in international waters throughout the exercise.

“At the closest point, some ships operated approximately 20 to 30 nautical miles (23 to 34 statute miles) off the coast of Hawaii,” he said. “We closely tracked all vessels.”

The Russian vessels had been located more than 300 miles west of the main Hawaiian Islands for parts of the drills.

The deployment of Russian “Bear” bombers as part of the exercise twice resulted in missile-armed Hawaii Air National Guard F-22 fighters scrambling to possibly intercept the turboprop planes — which headed in the direction of Hawaii but never came close, officials said.

The Hawaii Air Guard stealth jets launched June 13 and again on Friday, but no intercepts were conducted with the Russian planes likely turning away from the path toward the state, according to an account of the launch.

Record numbers of Russian aircraft intercepts off the West Coast has put a strain on U.S. units, Lt. Gen. David Krumm, head of U.S. Northern Command’s Alaska branch, said in late April, Air Force Times reported.

“We have certainly seen an increase in Russian activity,” the publication quoted Krumm saying. “We intercepted over 60 aircraft last year. … We monitor more than that.”

The San Diego-based aircraft carrier USS Carl Vinson — the first to support newer F-35C stealth fighters — arrived in the Hawaiian Islands operating area last week for drills that coincided with a Russian auxiliary general intelligence, or AGI, surveillance ship shifting from a spot off Kauai to international waters north of Oahu.

A Navy release dated last Wednesday said units assigned to Carrier Strike Group 1 were in the Hawaiian Islands Operating Area and working on integrated training with the U.S. Army, Marine Corps, Air Force, and Coast Guard.

“Operating in Hawaii provides unique opportunities for Vinson to train jointly while positioned to respond if called,” Vice Adm. Steve Koehler, commander of the San Diego-based U.S. 3rd Fleet, said in the release. “They train to a variety of missions, from long-range strikes to anti-submarine warfare, and can move anywhere on the globe on short notice.”

The Carl Vinson, the flagship of the carrier strike group, was operating with Carrier Air Wing 2, Destroyer Squadron 1, the guided-missile destroyers USS O’Kane, USS Howard, USS Chafee, USS Dewey and USS Michael Murphy. The Chafee and Michael Murphy are based at Pearl Harbor.

“Training in the (Hawaiian Islands area) is an exciting opportunity to integrate with the other services in order to promote peace and maintain a free and open Indo-Pacific,” said Rear Adm. Dan Martin, commander of the carrier strike group. “We look forward to enhancing partnerships within the joint force as well as strengthening relationships with our allies and partners in the region.”

U.S. Naval Institute News said the carrier strike group is preparing for a deployment later this summer.

The Navy said Vinson would be conducting “combat efficiency operations” including integrated flight operations with its aircraft and land-based Marine Corps and Air Force fighter squadrons, as well as U.S. Coast Guard C-130s cargo planes.

Last August, Vinson completed 17 months of maintenance, making it the first aircraft carrier equipped to support both the F-35C Lightning II and CMV-22B Osprey, the Navy said.

The F-35 “is the most lethal, survivable and connected fighter aircraft in the world, giving pilots an advantage against any adversary,” maker Lockheed Martin said on its website.

The CMV-22B Osprey is a variant of the tilt-rotor MV-22 operated by the Marine Corps out of Kaneohe Bay and is the replacement for the C-2A Greyhound for routine transport missions. The Osprey can take off and land like a helicopter but transits to a turboprop aircraft by rotating its huge propeller blades forward.

The F-35 Lightning II family includes three variants, all single-seat jets.

Lockheed Martin said the F-35A is designed to operate from conventional runways and is the most common variant. The United States Air Force and the majority of F-35 international allied customers operate the F-35A.

The F-35B can land vertically like a helicopter and take off in very short distances — allowing it to operate from austere, short-field bases and some ships. The F-35B is operated by the Marine Corps, the United Kingdom, and the Italian Air Force, Lockheed Martin said.

The F-35C, operated exclusively by the Department of the Navy, is the service’s first stealth fighter and is designed and built for aircraft carrier operations.

Russian officials said the exercise off Hawaii was its largest drills in the Pacific since the end of Cold War, CBS News had reported Tuesday. A U.S. official confirmed it was the largest such Russian exercise to be held this close to Hawaii in a long time.

“At the same time, officials said a U.S. carrier strike group headed by the USS (Carl) Vinson is operating about 200 miles east of Hawaii, conducting a strike group certification exercise,” CBS said. “The exercise had been planned but was moved closer to Hawaii in response to the Russian exercise.”

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 on Friday that the Russian spy ship, then north of Oahu in international waters, could be monitoring the carrier strike group.

“They don’t have to get close” to do that, he said.

“They (the Russians) have a deep and abiding and ongoing interest in whatever we’re doing with our carriers,” Schuster said. There’s been “a lot of discussion about what the Navy is going to do in future wars — how do we fight,” and talk about innovative tactics. “I’ll bet money that AGI is monitoring the Vinson.”