US Secretary of State Hillary Clinton has inspected and praised the $300 million Techport defence facility on her official visit to Adelaide.
Premier Jay Weatherill said Mrs Clinton's visit to the naval hub at Osborne was an important time for the state.
"This is regarded as the nation's premier maritime precinct, regarded as the most significant and important in the southern hemisphere, so it's a wonderful opportunity to showcase South Australian skills and capabilities," he said.
There was a high police and security presence across Adelaide for the Secretary of State's visit, most noticeably in the city centre, where the large entourage stayed at the Intercontinental Hotel.
Mrs Clinton's first official duty was a visit to Government House for a meeting with the Premier and the SA Governor Kevin Scarce.
She gave a wave as she arrived at Techport, then toured the facility, which Australia is keen to see used as a servicing hub for US warships during Pacific voyages.
Any such commitment from the US is unlikely to be given while Mrs Clinton is in town.
In an official address at Techport, Mrs Clinton said American defence manufacturers were helping modernise Australia's defence forces and Australian defence manufacturers, in turn, were contributing to US defence projects.
Three destroyers are being assembled at Techport and Mrs Clinton said the work was critical to Australia's defence and its role in achieving global peace and stability.
"Adelaide is from our perspective one of the great critical industrial centres in the world, the heart of Australia's defence manufacturing and a place where American and Australian companies work in close partnership every day," she said.
Mrs Clinton said the relationship between Australia and the US was "indispensable".
She said anyone who thought Australia needed to choose between the US and China was wrong.
"That kind of zero sum thinking only leads to negative sum results," she said.
"We support Australia having strong multi-faceted ties with every nation in the Asia Pacific indeed in the world, including China, just as we seek the same." Mrs Clinton spends another night in Adelaide before she flies out for Singapore and Bangkok on Friday morning.