U.S. President Donald Trump's combative envoy to Germany, Richard Grenell continues to draw fire from German officials for trying to intervene in the country's affairs.
"Mr Grenell is a total diplomatic failure," Carsten Schneider, head of the Social Democratic Party (SPD)' s parliamentary caucus, told the dpa in Berlin after ambassador Grenell criticized Berlin's decision to move more slowly toward the NATO spending target of 2 percent of gross domestic product.
Grenell's tone had long been inappropriate to relations between close allies, Schneider said, charging the ambassador with failure to recognize Germany's contribution within the alliance, in Afghanistan for example.
"Mr Grenell is harming transatlantic relations with his repeated heavy-handed remarks," he said.
Grenell has also faced criticism for his handling of U.S.-German disagreements over trade, a 2015 Iran nuclear deal and the Russian-led Nord Stream 2 gas pipeline.
The envoy last week warned German Economy Minister Peter Altmaier in a letter that security concerns could throttle U.S. intelligence sharing with Berlin if Huawei got a role in Germany's 5G next-generation mobile infrastructure.
Merkel told reporters the German government was keenly focused on security of digital networks, including the 5G mobile infrastructure, but Berlin would keep its own counsel.
Michael Grosse-Broemer, a conservative leader in parliament, said Germany was competent to address its own security, adding, "There is no need for pointers from the U.S. ambassador."
Grenell also sparked controversy in Germany when he warned German firms to start closing down their business operations in Iran.
His threat to slap sanctions on German firms involved in the Nord Stream 2 pipeline also proved counterproductive, shutting down potential critics of the project as German politicians are reluctant to be seen as bowing to U.S. pressure, experts said.
"Political smoothness is not his thing and he's proud of that. You could say he was the most undiplomatic diplomat Washington ever had here," said Ruediger Lentz, executive director the Aspen Institute Germany.