A 21-year-old member of the US Marine Corps is taken to hospital after returning a positive coronavirus test. It comes ahead of a military training exercise that will see thousands of military personnel rotate through Darwin by June.

Health authorities say the man was among the first group of about 200 marines to arrive, with soldiers touching down in Darwin on Thursday before entering quarantine at RAAF Base Darwin.

He is asymptomatic but will remain at the Royal Darwin Hospital until he recovers.

While the first two groups of marines will undertake their fortnight of quarantine in accommodation on Defence bases, further groups will be taken to Bladin Village, a privately owned former detention centre outside of Darwin.

As the Marine Corps reorganizes to prepare for a potential conflict with China, the service is considering three new Marine Littoral Regiments for its campaign of land warfare in the Indo-Pacific.
The service is shedding its heavier equipment so it can operate between expeditionary bases on islands in the Pacific to support the fleet. Part of the force design initiative is standing up a new unit, known as a Marine Littoral Regiment, which will likely have 1,800 to 2,000 sailors and Marines. The unit will feature a Littoral Combat Team, a Littoral Anti-Air Battalion and a Littoral Logistics Battalion.

Brig. Gen. Benjamin Watson, the commanding general of the Marine Corps Warfighting Lab, recently said the service plans to have the first regiment, which will be based in Hawaii, reach initial operational capability in Fiscal Year 2023.

“There has been discussion of creating as many as three in the Pacific between now and 2030 and they would be forward-based in the Pacific, although they might – depending on the experimentation that we do – they might be rotational in terms of how we source some of the people that man these Marine Littoral Regiments,” Watson said last week at the National Defense Industrial Association’s virtual expeditionary warfare conference.

“And then based on their – where they’re home-based in the Pacific, elements would rotate on a regular basis further west,” he continued. “So working with allies and partners so that we persistently have a presence from each of the Marine Littoral Regiments out there in the western Pacific.”

The Marine Corps is slated to stand up the first MLR in FY 2022

All 2,200 US marines will need to do a do a COVID-19 test and be able to show a negative result before boarding the plane to Australia.

The Department of Defence says each marine will have to do a coronavirus test within 72 hours of their departure and show a negative result before boarding the plane to Australia.

After they touch down in the Northern Territory, the marines will have to do another COVID-19 test and then undertake 14 days of quarantine. Before leaving quarantine, each person will be tested again for COVID-19.

To accommodate the large group, the Marine Rotational Force — Darwin (MRF-D) unit has rented a secure facility outside the NT capital for most of the US arrivals to quarantine in.

The first two groups, however, will quarantine in isolated accommodation on an unnamed Australian Defence base.

The arrival of the 2021 cohort will be the 10th annual rotation of US marines in Darwin.

The Biden Administration will likely be "focussed on national securities," meaning Australia may have to make harder choices in the defence space, according to the Lowy Institute’s Richard McGregor.

“Trump was focussed on trade,” Mr McGregor told Sky News. “The Biden Administration might be much more focussed on national securities.

“That might mean harder choices for us in the defence space.”

Mr McGregor said this may mean the US would expect Australia to look at things including “intermediate range missiles” and the possible placement of “more Marines in Darwin”

“They might like us to do greater naval exercises in the South China Sea,” he said. “I think they’re going to expect us to step up as a strong ally.”

As tensions between the US and China continue to simmer, researchers say the Biden administration could put a strategic spotlight directly on the NT's capital, given its proximity to Asia.

"There will probably be a rotational agreement like what we see with the Marines and the Air Force, but with some US Navy warships," Mr Thomas-Noone told ABC Radio Darwin.

Professor John Blaxland, of ANU's Defence Studies Centre, said Darwin would "likely see considerable additional attention in the coming weeks and years".

He said with the new administration "likely to continue to apply pressure on China" and come looking to Australia for additional help, it may be the Top End city that answers the call.

"Darwin's going to be more on the crosshairs than it has been for some time now," Professor Blaxland said.