But the US President defended the proposals to impose duties of 25 per cent on steel and 10 per cent on aluminium as early as next week by tweeting that "trade wars are good, and easy to win".
Ross played down the possible effects of the proposed tariffs on the U.S. economy.
But the amounts that they're talking about are also pretty trivial.
The problem with this for the U.S government, according to Peter Navarro - the White House trade official - is that excluding one country will create a slippery slope.
"In Ross" words: "Overall it's not going to be much more than a rounding error". "IF YOU DON'T HAVE STEEL, YOU DON'T HAVE A COUNTRY!" he challenged.
Some of these players are now warning: they may soon start implementing their own safeguards, like Europe did in 2002, after then-U.S. President George W. Bush imposed steep steel tariffs that drove excess metal their way.
Canada has the largest share of steel imports to the USA at 16 percent, according to data from the Department of Commerce, followed by Brazil and South Korea, with steel imports from China down 5 percent in the most recent period. After that, USA administrations imposed protectionist policies, only to see global competitors adapt and the US share of global steel production decline. They say they have been put at a disadvantage against foreign competitors for far too long.
"If policies are made on the basis of mistaken judgments or assumptions, it will damage bilateral relations and bring about consequences that neither country wants to see", he said.
The proposal has raised fears of an global trade war involving China and Europe.
China's Zhang Yesui, spokesperson for China's National People's Congress, said China would take "necessary measures" if its interests were hurt.