Australian Prime Minister Malcolm Turnbull on Wednesday said the U.S. will not gain anything by imposing tariffs on steel and aluminium, and a trade war will only curtail opportunities and choices for the citizens.
While Canada and Mexico have won 30-day exemptions, Mr Turnbull is the only national leader to secure a deal to avoid the USA tariffs of 25 per cent on steel and 10 per cent on aluminium.
Mr Turnbull said Mr Trump had acknowledged the trade relationship between Australia and the USA was a fair and reciprocal one.
"Great discussion today on security and trade".
BlueScope ships Australian steel to the USA west coast to make into roofing products because of the high cost of freight from the east coast.
Mr Trump's tweet came a day after he imposed tariffs of 25 per cent on steel and 10 per cent on aluminium.
"Australia/US trade is fair & reciprocal & each of our nations has no closer ally", the prime minister wrote on Twitter.
"Spoke to PM TurnbullMalcolm of Australia".
Trump initially said Canada and Mexico were the only countries granted exemption from the tariffs, but that was conditional on the two countries conceding to America's demands on other trade issues.
BlueScope chief executive Mark Vassella was at the AFR summit with the prime minister, who he said had "worked really hard" to get an exemption.
Turnbull said Saturday that Australia and the United States have a fair and reciprocal trade relationship.
"I had a frank discussion with the United States side about the serious pending issue of steel/aluminum tariffs, " the top European Union trade official, Cecilia Malmström, wrote on Twitter after the meeting.
"History tells us they are bad, and they end up causing not just a contraction in the global trade but, as a result of that, a contraction in global growth", he told ABC.
The U.S.is the world's largest importer of steel, importing almost four times as much as it exports, according to the White House.
Australian steel and aluminium to the United States were worth just over $400 million previous year.