US President Donald Trump is poised to unveil sweeping new "Liberation Day" tariffs on Wednesday, but kept the world guessing until the last minute about the scope of an onslaught that could spark a global trade war.

Trump will roll out the measures flanked by cabinet members in the Rose Garden of the White House at 4:00 pm (2000 GMT) -- after Wall Street markets close -- promising that they will stop America being "ripped off" and will deliver a new "golden age" of US industry.

But while Trump insisted he had decided on the reciprocal tariffs hitting countries that have targeted the United States, the White House admitted he was still ironing out the details with less than 24 hours to go.

The Republican billionaire has had a long love affair with tariffs, insisting in the face of economic experts that they are a cure-all that will tackle America's trade imbalances with friends and foes alike.

Critics say that not only will US consumers bear the brunt as importers pass on the cost, but that they could increase the risk of a damaging recession at home and abroad.

Global markets have been jittery for days ahead of Trump's announcement, while the........

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