A top German politician is calling for the expulsion of U.S. Ambassador Richard Grenell, who he says is acting like “a high commissioner of an occupying power.”

Grenell, a former Republican operative with a penchant for outrageous statements, has angered opposition lawmakers in Germany, who claim he is interfering in sovereign German matters.

Wolfgang Kubicki, the deputy chairman of the opposition Free Democrats (FDP), called on Germany’s foreign minister to “declare Richard Grenell persona non grata immediately.”

And he was not the only one criticizing the American ambassador.

“Grenell is a complete diplomatic failure. [He] damages trans-Atlantic relations with his repeated clumsy provocations,” Carsten Schneider, a lawmaker with the Social Democrats (SPD), told the German news agency DPA.

Grenell, 52, has done little to ingratiate himself to his host country since taking up the position in May 2018. Comments he made this week about Germany’s contributions to NATO led to Kubicki’s rebuke.

Donald Trump has clashed with Chancellor Angela Merkel repeatedly over Germany’s NATO spending, and it's not the only cause of tension between the two leaders. Merkel has also been spearheading an unprecedented summit between EU leaders and Chinese President Xi Jinping — and on Tuesday she said Berlin would not be following Washington’s demands that Chinese telecoms giant Huawei be banned from helping to build its 5G infrastructure.

In his remarks, Grenell criticized the budget of Germany’s finance minister and said it was unacceptable that the country was once again going to miss its NATO defense spending target.

Grenell said Germany’s plan to lower military spending to 1.25 percent of its gross domestic product by 2023 was a “worrisome signal to Germany's 28 NATO allies,” adding that it should stick to the 2 percent goal and “not run away.”

A member of Merkel's conservative alliance urged Grenell to show some restraint, reminding him that Germany meets many of its NATO obligations.

“If one keeps an overall view, many comments made are more coherent than those of the American ambassador, if he thinks he has to comment on something every week,” Michael Grosse-Brömer said.

Grenell should know better, given his seven years as U.S. spokesperson at the U.N., serving under then-U.N. ambassador John Bolton, Trump’s current National Security Adviser.

After leaving his U.N. post, Grenell founded his own communications company and was a regular contributor to Fox News. Grenell briefly acted as a spokesperson for Mitt Romney during his 2012 election campaign, becoming the first openly gay person to hold such a position.

Grenell was appointed in the hope his prior diplomatic experience would stand him in good stead, but this is far from the first time he's upset his hosts.

Over the weekend, in an interview with Breitbart, Grenell appeared to suggest he would work to topple Germany’s centrist government.

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

In January, Grenell demanded Berlin stop development of Nord Stream 2, the gas pipeline being laid across the Baltic Sea to bring gas from Russia to Germany.

“We emphasize that companies involved in Russian energy exports are taking part in something that could prompt a significant risk of sanctions," the ambassador wrote in a letter sent to the German newspaper Bild Am Sonntag.

Grenell’s appointment was strongly opposed by Democrats, who highlighted his previous undiplomatic outbursts. Within hours of being appointed German ambassador, those fears appeared well-placed, when Grenell tweeted what was seen as a threat to German businesses.