A US Congressional Research Service report has raised doubts about selling nuclear submarines to Australia under the Aukus agreement. The report suggests the US might keep the submarines under its own control rather than transfer them to Australia. This is due to concerns that Australia has not promised to support the US in a conflict with China over Taiwan. "Selling three to five Virginia-class SSNs to Australia would convert those SSNs from boats that would be available for use in a US-China crisis or conflict into boats that might not be available," says the report. The current plan under Aukus is for Australia to buy three to five Virginia-class nuclear submarines starting in 2032, then build eight UK-designed subs by the 2040s. But an alternative plan would keep the subs under the US Navy’s command, operated out of Australian bases. This would let Australia save money and invest in other defense tools like long-range missiles and drones. The report also highlights cyber threat risks from China, saying sharing nuclear sub technology would increase potential access points for hackers. The US shipbuilding industry’s struggles add to the challenge, with production rates below targets needed to supply both the US and Australia. Laws require the US President to confirm that selling subs to Australia will not weaken US undersea capabilities. Australia's strict no-nuclear weapons policy for its subs also limits the US’s options. The report notes that selling subs to Australia would be an unprecedented move, showing strong US-Australia-UK unity against China’s military growth. It would also help Australia develop a quicker submarine fleet, complicating China’s plans in the Indo-Pacific. The report compares this assistance to past US help to the UK and France in building nuclear fleets. Australia has rejected any plan other than directly acquiring submarines under Aukus. The Guardian has sought comment from Australia's Defence Minister Richard Marles.