President Trump resumed his criticism of the European Union on Thursday, assailing the bloc for the record antitrust fine it levied against the Silicon Valley giant Google this week.

Mr. Trump has repeatedly denounced the 28-nation group, America’s biggest trading partner, for what he says are its unfair economic policies. His administration has imposed stiff tariffs on aluminum and steel imported from European Union companies, and is also considering placing similarly hefty levies on European cars and car parts.

The president’s broader protectionist push, his specific labeling of the European Union as a “foe” on the issue of trade and his remarks raising questions about his commitment to NATO have led to a substantial cooling of the relationship between the longtime trans-Atlantic allies.

The European countries have sought to tamp down the rhetoric — Jean-Claude Juncker, the European Commission president, is to meet with Mr. Trump next week — but they have also refused to back down in the face of the president’s threatened tariffs.