An endangered dugong found dead here is believed to be one of only three that had been confirmed in waters around the northern part of this southern island.

The bureau is monitoring the mammals, designated by the central government as a protected species, whose habitat could be affected by land reclamation work for the relocation of U.S. Marine Corps Air Station Futenma in Ginowan to the Henoko district of Nago, both in Okinawa Prefecture.

Okinawa is said to be the northernmost limit of the habitat of dugongs.

Environmentalists have argued that the relocation project would destroy their critical habitat and called for a halt to the land reclamation work.

Japan's Prime Minister Shinzo Abe will make a historic visit to Darwin this November to help cement modern day relations with Australia.

Shinzo Abe is scheduled to be welcomed to the Northern Territory by Prime Minister Scott Morrison in November, before both men fly to Port Moresby for the APEC meeting of regional leaders.

Japan's massive $34 billion INPEX gas pipeline project will be the focus of Mr Abe's visit, but closer military ties are also expected to be high on the agenda when the two leaders meet.

Mr Abe's is the first visit to Darwin by a Japanese leader since forces struck the key military port, killing more than 250 people across multiple bombings in 1942 and 1943.

Top end diplomatic tango: Japan and US compete for attention. In mid-November Australia's top end will be the stopover point for regional leaders straddling two major meetings, the East Asia Summit in Singapore and the APEC gathering in Port Moresby a few days later. The ABC can reveal that during the brief period between the two summits, United States Vice-President Mike Pence will stay in Cairns, at the same time that Mr Morrison hosts his Japanese counterpart in Darwin. Mr Pence, who met with Mr Turnbull during a visit to Sydney in 2017, is expected to fly into the APEC summit each day from northern Queensland rather than staying overnight in Port Moresby.

Japan’s military could conduct exercises out of Darwin under a historic defence agreement being negotiated by Malcolm Turnbull and Shinzo Abe, as part of a multi-pronged strategy to counter China’s growing influence in the Indo-Pacific.

The wide-ranging agreement, which will also allow military equipment and ammunition to be transported far more easily between the countries, will be progressed during the Prime Minister’s trip to Tokyo next week, as Australia faces a growing row with China over government criticism of Beijing’s Pacific aid.

Mr Turnbull will arrive in Tokyo on Thursday to meet the Japanese Prime Minister, who has been keen to amend his country’s post-World War II constitution to give the military a more legitimate role on the world stage. The trip follows Mr Abe’s visit to Australia last year.

Australia and Japan have championed building up regional alliances — such as the revived Quadrilateral Security Dialogue between Japan, India, the USA and Australia — in the face of China’s increasing dominance in the ­region.

Mr Turnbull has said he and Mr Abe will discuss a new visiting forces agreement, a type of ­arrangement that Japan has with one other country — the USA.

Australian Strategic Policy ­Institute head Peter Jennings said he expected the deal would allow for Japanese forces to conduct ­exercises in Australia.

"I’d expect there’d be an ­opportunity for more army ­engagement, including, ironically enough, perhaps out at Darwin, maybe doing trilateral activities with the US marines there.”

the deal is expected to be signed this year, paving the way for the Japanese Self-Defence Force troops to train in Australia.

A U.S. warship struck by a container vessel in Japanese waters failed to respond to warning signals or take evasive action before a collision that killed seven of its crew, according to a report of the incident by the Philippine cargo ship's captain.

Multiple U.S. and Japanese investigations are under way into how the guided missile destroyer USS Fitzgerald and the much larger ACX Crystal container ship collided in clear weather south of Tokyo Bay in the early hours of June 17.

In the first detailed account from one of those directly involved, the cargo ship's captain said the ACX Crystal had signaled with flashing lights after the Fitzgerald "suddenly" steamed on to a course to cross its path.

The container ship steered hard to starboard (right) to avoid the warship, but hit the Fitzgerald 10 minutes later at 1:30 a.m., according to a copy of Captain Ronald Advincula's report to Japanese ship owner Dainichi Investment Corporation that was seen by Reuters.

The collision tore a gash below the Fitzgerald's waterline, killing seven sailors in what was the greatest loss of life on a U.S. Navy vessel since the USS Cole was bombed in Yemen's Aden harbor in 2000.

Those who died were in their berthing compartments, while the Fitzgerald's commander was injured in his cabin, suggesting that no alarm warning of an imminent collision was sounded.

A spokesman for the U.S. Navy's Seventh Fleet in Yokosuka, the Fitzgerald's home port, said he was unable to comment on an ongoing investigation.

The Marine Corps this spring is sending its largest aircraft element to date -- four tilt-rotor Ospreys and five Super Cobra and four Huey helicopters, all out of Hawaii -- to the next $25 million rotation of Marines to northern Australia as the Corps continues to redistribute its forces around the Pacific.

The Marines are moving to four major forward areas of operation over the next decade -- Japan, Guam, Hawaii and Australia -- as part of a "distributed laydown" that seeks to deter growing threats in the vast Asia-Pacific region, particularly from from China and North Korea.

The Osprey, with its long range and speed, is seen as a key connector for the Marine Corps in its new island-hopping strategy.

In November 2011, President Barack Obama and Australian Prime Minister Julia Gillard announced that U.S. Marines would be sent on six-month rotational deployments to train with the Australian Defence Force in Darwin and elsewhere in the Northern Territory. The move puts the Marines closer to Southeast Asia and allows Australia, a key ally, to bolster its defense.

The presence was to grow to a 2,500-member Marine Air-Ground Task Force during the 2016-2017 time frame, but officials said the sixth iteration of the deployment will remain at 1,250 Marines who are expected to arrive in Australia in April.

Most of the Marines will be from the 3rd Battalion, 4th Marine Regiment, out of Camp Pendleton in California, Marine Corps Forces Pacific said.

According to Australia's Department of Defence, 200 Marines deployed in 2012, 250 in 2013, 1,150 in 2014, 1,150 in 2015 and 1,250 in 2016.

But the deployment number is stuck at 1,250 for the time being as funding problems continue to be worked out for the full Marine Air-Ground Task Force of 2,500 with aircraft, vehicles and other equipment.

"The Marine Corps position to date has been that we will not grow the force beyond 1,250 Marines in Australia until we get some top-line (overall Marine Corps budget) relief for funding for military construction," Craig Whelden, executive director of Marine Corps Forces Pacific at Camp H.M. Smith, said at a recent Chamber of Commerce Hawaii event.

Whelden added that "we've essentially tapped out what we can use of existing facilities and for sustainment." The deployment of 1,250 Marines costs about $25 million, he said. Marine Corps Forces Pacific is the tasking authority for the units participating in the rotations.

Australia and the United States in October agreed to a more than $1.5 billion cost-sharing agreement to improve infrastructure in northern Australia as well as pay for ongoing costs over the 25-year pact -- ending a disagreement over who would pay the tab, The Australian newspaper reported.

Australian media also said the Marine Corps rotational force is expected to double to its full strength of 2,500 by 2020.

The four Hawaii MV-22 Ospreys scheduled to make the deployment are from Marine Medium Tilt Rotor Squadron 268 (VMM-268), while the five AH-1W Super Cobra and four UH-1Y Venom helicopters are part of Marine Light Attack Attack Helicopter Squadron 367 (HMLA-367). The Aviation Combat Element of 13 aircraft will be hosted at Royal Australian Air Force Base Darwin.

By comparison, the Marines sent four UH-1Y helicopters for the rotational deployment in 2016 and four big CH-53E Super Stallions in 2015, according to Australia's Defence Department.

Whelden called the next contingent to deploy "a more diversified, a more capable force than we've had previously."

The "distributed laydown" in the Pacific, which dovetails with the Marine Corps' expeditionary nature and ability to rapidly move forces from one place to another, calls for moving more than 4,000 Marines from Okinawa, Japan, to Guam. Whelden said hundreds of millions of dollars already have been invested on Guam, with wharves to support amphibious ready group ships already completed and ramp and hangar work ongoing for Ospreys and the new F-35B Lightning II, which the Corps called the "world's first operational supersonic short takeoff and vertical landing fighter." "We aren't basing F-35s in Guam, but we train on Guam a lot," Whelden said. Ten of the stealth fighters this week were sent to Iwakuni, Japan, with six more expected to arrive this summer. Whelden said the relocation of about 2,700 Marines from Okinawa to Hawaii is about 10 years away.