Long-threatened tariffs from U.S. President Donald Trump have plunged the country into trade wars abroad — all while on-again, off-again new levies continue to escalate uncertainty.

Trump said this would boost U.S. exports of beef, ethanol and other goods — though details on food standards still need to be worked out. The 10% U.S. tariff on imports of most British goods remains.

President Donald Trump hailed what he said would be "a very big and exciting day" for the U.S. and U.K. on Thursday after earlier touting a "MAJOR TRADE DEAL" that the countries are due to announce. The two sides are expected to outline an agreement on "heads of terms" for an eventual full trade deal,