BERLIN (Reuters) - U.S. President Donald Trump’s new ambassador to Germany, Richard Grenell, warned German companies to halt activities in Iran after the U.S. leader said Washington was pulling out of the Iran nuclear deal and would reimpose sanctions. 
 
 Grenell, a long-time critic of the 2015 nuclear deal, posted the warning on Twitter just hours after arriving in Berlin and presenting his credentials to the German president. 
 
 Trump made the announcement in a televised address from the White House, in a move that will raise the risk of conflict in the Middle East, upset Germany and America’s other European allies, and unsettle global oil markets. 
 
 “US sanctions will target critical sectors of Iran’s economy,” Grenell said in his first posting on Twitter after arriving in Germany. “German companies doing business in Iran should wind down operations immediately.” 
 
 German industry reacted nervously to the U.S. announcement, warning that European companies could face U.S. fines if their Iranian business partners wound up on U.S. sanctions lists. 
 
 Grenell is starting his job in Berlin nearly 16 months after his predecessor John Emerson left the country. 
 
 A Republican foreign policy writer and avid Twitter user, Grenell was an aide to Trump’s new national security adviser, John Bolton, when Bolton was former Republican President George W. Bush’s ambassador to the United Nations. Grenell served as the U.S. spokesman at the United Nations from 2001 to 2008, and then worked as a contributor to Fox News. 
 
 The U.S. Senate confirmed Grenell on April 26, making him the highest-ranking openly gay official in the Trump administration. The next day, he joined Trump at the White House to welcome Chancellor Angela Merkel for talks that produced little movement on trade disputes or the Iran accord. 
 
 Trump had nominated Grenell in September but key Democrats help up his confirmation, citing concerns about what they called Grenell’s history of making statements insulting to women politicians on the internet and during television appearances. 
 
 Asked about such comments during his confirmation hearing, Grenell said he was trying to be funny, not insulting, and would not have made such statements while serving as a U.S. public official. ||||| Tweet with a location 
 
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 Guests at the elegant cocktail party — hosted by Bill White and Bryan Eure at their sprawling Chelsea apartment — included Donald Trump Jr., who gave a toast and railed against the Democrats for holding up Grenell’s confirmation. 
 
 Don Jr. continued, “I look forward to you [Richard] going there, because every time . . . I read about what is going on there and everywhere else, I don’t know if I’m reading a newspaper or if I’m reading the Onion. I look forward to seeing someone who is not afraid to speak up and fight for what’s right.” 
 
 He added, “And I look forward to visiting . . . As long as they don’t say I am somehow colluding with the Germans.” 
 
 Grenell — the highest-ranking gay official in the administration — told the crowd, “I really want to thank President Trump for believing in me, and pushing hard when a lot of other people said no . . . I believe not being a part of the Washington culture is the exact reason I am here today.” 
 
 Bill O’Reilly was a surprise guest, and said in a speech to the crowd, which included Sarah Huckabee Sanders, that “heads would have rolled” if he’d been at the White House Correspondents’ Dinner, and, “I would love just to get my big hands around Jim Acosta’s neck.” 
 
 O’Reilly told Page Six of the allegations against other newsmen such as Charlie Rose and Tom Brokaw, “I don’t know the specifics, but each case deserves its due course. There is not a lot of sympathy out there [for accused men].” 
 
 Other guests included former press secs Ari Fleischer and Dana Perino, former Gov. George Pataki, Terry Allen Kramer, and Fox News’ Martha MacCallum, Harris Faulkner, Kimberly Guilfoyle and Greg Gutfeld — plus Wayne Newton, who serenaded all with (thankfully, but hilariously) just one verse of his ’60s hit “Danke Schoen.”
– Richard Grenell's first day on the job may not have gone exactly how he imagined it. The brand new US ambassador to Germany arrived in Berlin on Tuesday, and in the span of little more than an hour, three things occurred: Grenell handed his credentials to Germany's president, President Trump announced the end of America's participation in the Iran nuclear deal, and Grenell raised some German ire. It's all due to this tweet, made shortly after Trump spoke: "As @realDonaldTrump said, US sanctions will target critical sectors of Iran’s economy. German companies doing business in Iran should wind down operations immediately." Reuters notes Grenell has himself long-opposed the nuclear deal. That sentiment aligns with the White House's—indeed, Grenell, a former Fox News contributor who Page Six notes had an "A-list" going away bash, subsequently tweeted that he directly lifted the language from documentation provided to him by the administration. But the Washington Post observes that "the timing and tone struck some German politicians, journalists and businessmen as offensive and inappropriate." It characterizes the tweet as coming off as a threat and rounds up plenty of reaction, including this from the leader of the country's Social Democratic party: "It’s not my task to teach people about the fine art of diplomacy, especially not the US ambassador. But he does appear to need some tutoring." Grenell, the administration's top-ranking openly gay official, fills an ambassadorship that has been empty for 16 months.