Grenell presented his credentials to the President of Germany on May 8, 2018.[38] Within hours of taking office, Grenell offended diplomats and business leaders when he tweeted that “German companies doing business in Iran should wind down operations immediately.”[39] The tweet was widely perceived as a threat, with the Foreign Minister of Luxembourg, Jean Asselborn, commenting that "This man was accredited as ambassador only yesterday. To give German businesses such orders … that’s just not how you can treat your allies.”[40] The leader of Germany's Social Democratic Party stated that Grenell "does appear to need some tutoring" in the "fine art of diplomacy", while the Die Linke party urged the Merkel government to summon Grenell to explain his comments.[40]