Australian Prime Minister Malcolm Turnbull said on Friday he is hopeful of securing an exemption from US tariffs on steel and aluminium after sustained lobby effort by his government.
Trump tweeted on Friday that "Working very quickly on a security agreement so we don't have to impose steel or aluminum tariffs on our ally, the great nation of Australia!"
But it is an export market worth hundreds of millions of dollars to Australian businesses nevertheless.
"Spoke to PM TurnbullMalcolm of Australia".
It buys about 60 percent of its military assets from the United States, allows Marines to rotate through Darwin every year, and swaps intelligence with Washington.
Meanwhile, Mr Willox welcomed Australia's signing of the Trans-Pacific Partnership trade pact and said the United States may sign up once it sees the benefits to other members. He said the conversation also touched on the security alliance between the USA and Australia, as well as possible talks between Trump and North Korean leader Kim Jong Un. "No immediate clarity on the exact United States procedure for exemption however, so discussions will continue next week".
The European Union, the world's biggest trade bloc, chimed in.
The EU is also readying a list of countermeasures targeting about $3.5 billion in annual trade. Trump also mentioned Australia when speaking to reporters at the White House earlier in the day.
Trump insists surplus production of those metals in China has been pushing down global prices, and that the tariffs are necessary for national security. Instead, they said, Trump is bolstering domestic industries in violation of worldwide trade rules.
"We are living in historic times of unraveling, " he said.
Some European policymakers said they anxious the tariffs were part of a broader assault by the Trump administration on ties between Europe and Washington, which has been the backbone of the post-World War II Western order. Australia-US trade is fair and reciprocal and "each of our nations has no closer ally", he said.