Democratic Senator Jack Reed and Republican Senator James Inhofe wrote to US President Joe Biden late last year imploring him not to let the security pact between Australia, the US and the UK come at a cost to US capability.

They urged the president not to sell Virginia-class submarines to Australia, an option Opposition Leader Peter Dutton has been pushing as a way of filling a gap in Australia’s defence capability.

Reed is the chair of the Senate Armed Services Committee.

“Over the past year, we have grown more concerned about the state of the US submarine industrial base as well as its ability to support the desired AUKUS SSN (nuclear sub) end state,” the senators wrote in their December 21 letter that was later leaked.

“We believe current conditions require a sober assessment of the facts to avoid stressing the US submarine industrial base to the breaking point”.

In response to the leaked letter the Albanese government has stood by the nuclear-powered submarine project and says it remains on track.

On Tuesday, Reed tweeted his support for the “powerful partnership” struck in September 2021 by Biden, then Australian prime minister Scott Morrison and former UK leader Boris Johnson.

“I’m proud to support AUKUS, the United States’ historic military agreement with the UK and Australia,” Reed tweeted.

“This powerful partnership is central to ensuring a free and open Indo-Pacific, dramatically improving the capabilities of our allies, and increasing our engagement in the region.

“Importantly, AUKUS also lays the foundation for the most significant integration of our undersea and other military capabilities ever achieved.”

Reed said successful implementation of AUKUS required “responsible oversight and a stable industrial base”, particularly when it came to submarine programs.

Dutton has stood by his belief that the US should initially sell Australia two Virginia-class submarines ahead of acquiring its own nuclear-powered fleet.

-AAP