BERLIN — Richard Grenell is the United States’ top diplomat in Berlin, but Germans were questioning his diplomatic skills on Monday, after he said that he wanted to empower conservative leaders in Europe who dared to challenge what he called “the failed policies of the left.”

A Foreign Ministry spokesman said on Monday that the ministry had requested a clarification of remarks by Mr. Grenell, the new American ambassador to Germany, which were condemned on both sides of the Atlantic as lacking the neutrality expected of a diplomat. His statements came at a time when Berlin and Washington are at odds over President Trump’s moves to withdraw the United States from the Iran nuclear deal and the Paris climate accord — both of which Berlin supports — and to raise tariffs on steel and imports from Europe.

In a wide-ranging interview with Breitbart London that was released over the weekend, Mr. Grenell, who assumed his post just last month, said, “There are a lot of conservatives throughout Europe who have contacted me to say they are feeling there is a resurgence going on.”

“I absolutely want to empower other conservatives throughout Europe,” he said. “I think there is a groundswell of conservative policies that are taking hold because of the failed policies of the left.”