European leaders said they would respond firmly to higher levies on steel and aluminum, but they had yet to say what that retaliation would look like.

President Donald Trump signed an order Monday imposing global tariffs of 25% on all steel and aluminum imports in a move that will likely please domestic steelmakers but hurt allies like Canada and Mexico.

European shares were largely unchanged on Tuesday after a record close in the previous session, with investors assessing the risks of an escalating trade war after U.S. President Donald Trump raised tariffs on metals.