The US is sharing a once highly-guarded missile system that will make British and Australian nuclear submarines far more deadly

• The US is sharing submarine missile launch tech with allies to counter China.
• The subs would be equipped to fire hypersonic missiles capable of evading air defense.

The US is sharing once-secret submarine missile launch technology with Australia and the UK as part of a pact to counter growing Chinese military power in the Pacific region, reports say.

The US, UK, and Australia on Monday announced plans for Australia to obtain a new fleet of nuclear-powered submarines.

Under the AUKUS pact, which was first unveiled in 2021, the US will sell Australia three of its nuclear-powered submarines, while the UK and Australia will collaborate to build new vessels - a model that is being called SSN - AUKUS.

The deal will involve building at least eight nuclear-powered submarines for the Australian naval fleet, using UK designs, and underpinned by a US-made vertical launch system.

Sidharth Kaushal, an analyst at London's Royal United Services Institute, said that technology gives the submarines the capacity to fire hypersonic missiles, which can evade defense systems.

"Hypersonic missiles are important as they have the speed and range to penetrate defended airspace and hit hardened targets," he told Insider. "For nations which do not have stealth bombers (everyone excluding the US) they may represent the only way of striking targets at reach within well defended enemy airspace."

According to reports, the new Australian submarines will also have the capacity to fire cruise missiles through the vertical launch system.

The fact that they are nuclear-powered means the submarines can operate at far greater distances, and stay submerged for longer.

Until the AUKUS pact, the UK was the only country with which the US had shared its nuclear submarine technology.

The new Australian submarines will begin operation in the 2040s, and the new UK subs in the 2030s. In the interim, the US and UK will berth nuclear submarines in Perth, Western Australia.