U.S. Ambassador to Germany Richard Grenell attends the 4th of July party hosted by the U.S. Embassy at former Tempelhof Airport on July 4, 2019 in Berlin, Germany. Sean Gallup/Getty

Berlin — The U.S. Ambassador to Germany said he felt insulted this week when Germany's economy minister drew a comparison between the U.S. and China during a recent television appearance. Peter Altmaier was defending the German government's refusal to ban Chinese tech giant Huawei from building the country's 5G cellular network, saying if the company were indeed transmitting data to intelligence agencies in Beijing, it would be "no worse than what the U.S. has already done."

Altmaier noted that Germany had "not imposed a boycott" on U.S. tech firms after it was revealed that the U.S. National Security Agency had monitored cell phone calls in the country in 2013, and allegedly even spied on Chancellor Angela Merkel.

The U.S. has long called on its allies to boycott Huawei, warning that China could use the telecoms provider's equipment to conduct espionage or cyber sabotage. Altmaier pointed out that the U.S. "also demands that its companies pass on information needed for fighting terrorism."

His remarks drew a strong rebuke from the White House's man in Germany, Ambassador Richard Grenell.

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"The recent claims by senior German officials that the United States is equivalent to the Chinese Communist Party are an insult to the thousands of American troops who helped ensure Germany's security and the millions of Americans committed to a strong Western alliance," he said in a statement issued by the U.S. Embassy in Berlin. "There is no moral equivalency between China and the United States and anyone suggesting it ignores history – and is bound to repeat it."

To drive his point home, Grenell flagged at least a couple tweets this week to Altmaier's account linking to news articles about China's human rights abuses of Muslim minorities in the country.

Grenell's indignation was echoed by President Trump's National Security Adviser, Robert O'Brien, who noted that the U.S. was, "a country that sacrificed a lot of blood and wealth during the Cold War to protect Germany."

Altmaier's comments also caused a stir among senior German politicians. The reaction prompted him to say he had been misinterpreted.

"At no point did I draw parallels between the U.S. and Chinese political systems," he told Bild. "We need the highest possible security standards when dealing with sensitive data, no matter where the products originate."

Strained relations

U.S.-German relations have been tense since Mr. Trump's envoy to the country took office in May last year. Grenell has ruffled feathers with a number of controversial forays into Germany's domestic politics. Critics have accused him of flouting diplomatic norms and harming the transatlantic alliance.

On his first day as Ambassador in Berlin, he took to Twitter and called on German companies to "immediately" withdraw from Iran, against which the U.S. had just announced new sanctions. Germany has tried for months, along with France and Britain, to keep the 2015 nuclear deal with Iran viable after the Trump administration's unilateral withdrawal from it.

In response to that tweet, Wolfgang Ischinger, a former German Ambassador to the U.S. and now chairman of the Munich Security Conference, said: "Ric, my advice, after a long ambassadorial career: explain your own country's policies, and lobby the host country - but never tell the host country what to do, if you want to stay out of trouble. Germans are eager to listen, but they will resent instructions."

Grenell is an ardent backer of his boss President Trump's policies, and just a month into his job he expressed controversial support for Europe's right-wing political movements in an interview with Breitbart.

"I absolutely want to empower other conservatives throughout Europe, other leaders," Grenell said to the news site previously run by Steve Bannon. "I think there is a groundswell of conservative policies that are taking hold because of the failed policies of the left."

He presented himself as a "big fan" of the then-Austrian chancellor Sebastian Kurz, a right-wing conservative politician who espoused a tough stance in favor of limiting immigration to Austria and Europe more broadly.

Grenell dismissed accusations that he was interfering in Germany's internal affairs as "absurd."

"I stand by my comments that we are experiencing an awakening from the silent majority — those who reject the elites & their bubble. Led by Trump," he said in a tweet. Mr. Trump has consistently drawn low approval ratings across Europe, including in Germany and even among backers of the country's right-wing populist party, AfD.

In January of this year, Grenell again angered many in Germany by threatening German companies involved in the development of the Nord Stream 2 natural gas pipeline.

"Companies involved in Russian energy exports are taking part in something that could prompt a significant risk of sanctions," he said.