As promised while when route to the Super Bowl on Sunday afternoon, U.S. President Donald Trump announced increased tariffs on imported steel and aluminum late Monday and said America would hike its current 10 percent penalty to 25 percent by mid-March. Tuesday morning, the White House issued a fact sheet elaborating on President Trump’s planned action aimed at shoring up the country’s national security and “restoring fairness to steel and aluminum markets.”

America imported about 23 percent of its steel production last year, according to the American Iron and Steel Institute. The three biggest exporters were Canada, Brazil and Mexico, followed by South Korea, other Asian producers and the European Union.

Late last month, Brazilian President Lula da Silva threatened reciprocal tariffs should Trump should Trump hike steel tariffs first. On Tuesday, Canada and Mexico criticized the U.S. announcement, while the EU officials indicated European countries would retaliate in kind.

“Unjustified tariffs on the EU will not go unanswered – they will trigger firm and proportionate countermeasures. The EU will act to safeguard its interests,” European Commission head Ursula von der Leyden said. Europe had suspended tariffs on American bourbon, motorcycles and orange juice, but could restore these.

Canadian Prime Minister said in response he would “stand up” for workers and businesses. America currently imports about half its aluminum from Canada.

The heightened rhetoric and prospect of a global trade war is a more targeted return to last week’s round of heated exchanges between Washington, Beijing Ottawa, and Mexico City while bringing Europe into fray. If last week was any indication, these recent moves are a starting point for new negotiations.

Past U.S. administrations have imposed tariffs and then granted exemptions to various exporters. In 2019, Trump threatened steel tariffs but later reached new trade adjustments with key exporters.

How markets will react remains unclear. The S&P 500 was virtually unchanged Tuesday morning in the first hour of trading.