The United States, Britain and Australia have announced a new defense and security partnership for the Indo-Pacific.
As part of the deal, a fleet of nuclear-powered submarines will be built for the Australian Navy.
It sparked immediate condemnation by China.
The BBC's David Willis reports.
This announcement comes at a time of growing concern in Western capitals over China's military posture in the region.
The trilateral agreement will ultimately lead to more submarines patrolling one of the most contested trade routes in the world.
Nuclear-powered vessels can go further than conventionally powered ones and far more difficult to trace because they won't contain nuclear weapons.
Officials say sharing such technology will not constitute a breach of agreements such as the Non-Proliferation Treaty.