Leaked correspondence obtained by the ABC shows 11 fuel tanks built to support US military activities in the Indo-Pacific have been unlawfully constructed on Darwin Harbour.

Despite having an initial completion date of September 2023, the tanks are still not operational due to "water intrusion" in their leak detection system.

ABC has obtained correspondence from February 20, 2024 that shows the tanks were constructed without a building permit — a legal requirement under the Northern Territory Building Act.

The tanks' owner-occupier, US-based company Crowley, says it's working with the Northern Territory government to complete the project in compliance with the law.

Crowley said Project Caymus was issued a development permit in November 2021 "to allow the land to be developed for the project". The development permit, which has also been obtained by the ABC, explicitly notes that it "is not an approval to undertake building work".

US bombers were given air access in the Top End as part of their mission to target Houthi forces in Yemen, the Department of Defence has confirmed.

It remains unclear what damage or how many casualties were inflicted.

However, it was revealed the Australian Government had a role in the mission, with the Department of Defence confirming contribution.

“Australia provided support for US strikes conducted on 17 October 2024 targeting Houthi facilities in Yemen, through access and overflight for US aircraft in northern Australia,” a Defence spokesperson said.

Defence maintains the bombers did not operate from any Royal Australian Air Force base, contrary to speculation online which reported RAAF Base Tindal, in Katherine, to have launched the airframes.

The Department of Defence has confirmed Australia provided support for the US strikes on underground bunkers used by Yemen's Houthi rebels "through access and overflight for USA aircraft in northern Australia".

The US said its strikes were ordered by President Joe Biden to degrade the Houthi weapons stores and send a message to "our adversaries", which includes Iran.

An Australian official said the support was "consistent with our long-standing alliance commitment and close cooperation, demonstrating the interoperability of our militaries".

"It is a clear demonstration that the US Air Force can operate B-2s from forward Australian bases to deliver precision strikes at a range that could also encompass targets in China.

Deep in the outback, a flurry of construction by Australia and the United States is transforming this once quiet military installation into a potential launchpad in case of conflict with China.

Runways are being expanded and strengthened to accommodate the allies’ biggest airplanes, including American B-52 bombers. A pair of massive fuel depots is rising side by side to supply U.S. and Australian fighter jets. And two earth-covered bunkers have been built for U.S. munitions.

But the activity at RAAF Tindal, less than 2,000 miles from the emerging flash points of the South China Sea, isn’t unique. Across Australia, decades-old facilities — many built by the United States during World War II — are now being dusted off or upgraded amid growing fears of another global conflict.

Marles declined to comment on the increasing rotations ... but said the trajectory is “an increasing American force posture in Australia.”

As the US prepares to increase its military presence across northern Australia, a Darwin-based policy expert is urging the next Northern Territory government to land a “fair and reasonable deal” with the Commonwealth ahead of the arrival of American firepower.

The appeal comes after US Defense Secretary Lloyd Austin declared the US would deploy more personnel and combat aircraft to northern Australia amid escalating tension across the Indo-Pacific region.

“We’re also increasing the presence of rotational US forces in Australia, and all this will mean more maritime patrol aircraft and reconnaissance aircraft operating from bases across northern Australia,” Mr Austin told a press conference in Maryland.

“It will also mean more frequent rotational bomber deployments.”

While Mr Austin did not specify how many personnel or assets would arrive to Australia – or when – the announcement was met with enthusiasm by Solomon MP Luke Gosling, who said up to $18 billion would support the big move to the Territory.