GOTEBORG, Sweden — The European Union fought back on Friday against the Trump administration’s tariffs, slapping penalties on an array of American products that target the president’s political base, like bourbon, motorcycles and orange juice.

The European counterattack on $3.2 billion of goods, a response to the administration’s measures on steel and aluminum imports, adds another front to a trade war that has engulfed allies and adversaries around the world. China and Mexico have already retaliated with their own tariffs, and Canada, Japan and Turkey are readying similar offensives.

The risk of escalation is high since Mr. Trump has promised even more tariffs. Taking particular aim at German car manufacturers, the president has started an investigation into automobile imports to determine whether they pose a national security concern, the same justification used for his metal tariffs.

“You look at the European Union,” the president told a crowd in Duluth, Minn., on Wednesday. “They put up barriers so that we can’t sell our farm products in. And yet they sell Mercedes and BMW, and the cars come in by the millions. And we hardly tax them at all.” He added in a tweet on Friday that he would place a 20 percent tariff on European cars, if the barriers “are not soon broken down.”