Washington | A new $US500 million ($645 million) warship christened at the weekend will serve as a symbol for the Australia-US alliance as they celebrate the 70th anniversary of the ANZUS treaty.

The USS Canberra – which is the only US Navy ship to be named after a capital city outside the US – was first announced by then-president Donald Trump in 2018 when then-prime minister Malcolm Turnbull visited the US.