President Donald Trump said the U.S. was withdrawing from the 2015 nuclear deal because “the Iranian regime is the leading state sponsor of terror.”

Grenell put defenders of the nuclear accord, formally known as the Joint Comprehensive Plan of Action, on the defensive when he tweeted to his nearly 90,000 followers on Tuesday:

“As @realDonaldTrump said, US sanctions will target critical sectors of Iran’s economy. German companies doing business in Iran should wind down operations immediately.”

Grenell, a former Fox News contributor, previously served as spokesman for the U.S. mission to the United Nations.

After critics fired back against Grenell’s tweet, he wrote on Twitter that his message is “the exact language sent out from the White House talking points & fact sheet.”

Commenting on the Grenell Tweet and the blowback in Germany, Sen. Ted Cruz,  R-Texas, told on Friday that “Iran poses a direct threat to the United States and our allies. The Ayatollahs use Iran’s resources to pursue nuclear weapons that could hit the American homeland, to launch terror attacks, to seize Americans, and to threaten global shipping. Given our shared security interests, our European allies should work hand-in-hand with us to constrain Iran, not to enrich the regime.”

Senator Marco Rubio, R-Florida, told Friday that“The United States is taking a stand against the Iranian regime, a state sponsor of terrorism that materially supports dictator Bashar al-Assad’s war crimes in Syria and is therefore complicit in perpetuating the largest humanitarian and refugee crisis since World War Two. We urge our allies and partners to stand on the right side of history and stop doing business with the Iranian regime.”

George W. Bush’s former spokesman Ari Fleischer tweeted, with biting sarcasm and irony, about criticism targeting Grenell: “Note to all US Ambassadors: if you want good press coverage, defy the President who appointed you. Whatever you do, do NOT represent the position of the President of the US.”

Andrea Nahles, the chairwoman of the Social Democratic Party−a partner in Chancellor Angela Merkel’s coalition−said about Grenell, “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.”

Nahles has faced criticism for her 2012 embrace of the Palestinian Fatah party. She said her Social Democratic Party and Fatah have “shared values” and “common goals.”

Wolfgang Ischinger, the chairman of the Munich Security Conference and a former German ambassador to the U.S., commented on Twitter about Grenell, “Germans are eager to listen, but they will resent instructions.”

The German Left Party sharply criticized Grenell, telling Merkel to summon Grenell for a diplomatic dressing down. The Left Party is considered the “voice of Russia” in the German parliament because of its support for the policies of the authoritarian Vladimir Putin.

German-Iran trade has steadily risen since the nuclear deal was signed in 2015. German exports to the Islamic Republic climbed to 3.5 billion euros ($4.18 billion) in 2017 from 2.6 billion euros ($3.11 billion) in 2016. According to economic experts, annual bilateral trade could soon soar to 10 billion euros ($11.95 billion), unless U.S. sanctions have a major effect.

A spokesperson for Germany’s foreign ministry referred to a statement from foreign minister Heiko Mass delivered to the television program “Tagesscahau.” Mass said that “the Iran [agreement] is not dead.” He added that “Iran has an interest in economic contact to the world so it can develop prosperity in its country.”

In 2016, the European Union conducted 587 billion euros ($701.38 billion) worth of exports to the U.S while European exports to Iran amounted to 9.1 billion euros ($10.87 billion). European companies could face denied access to the lucrative U.S market if they continue business with Iran.

Germany became embroiled in a chemical weapons scandal with Iran in February. Construction material from the Stuttgart region-based Krempel Group was found in Iranian rockets used in two chemical attacks on Syrian civilians. The poison gas attacks injured 24 people. Germany’s Federal Office for Economic Affairs and Export Control (Bafa) defended the sales to Iran because the material was not classified as dual-use merchandise that can be applied for military purposes. Bafa did not ban further Krempel sales to Iran.

U.S. Jewish human rights organizations welcomed Grenell’s call for Berlin to pull the plug on business relations with Iran.

The Zionist Organization of America said on Thursday: “The ZOA thanks and praises new US Ambassador to Germany Rick Grenell for his efforts to obtain German companies’ compliance with economic sanctions on Iran. This is excellent advice.”

German industrial giants such as Siemens, Volkswagen, Mercedes Benz and the Linde Group conduct business with Islamic Republic.

Michael Tockuss, managing board member the German-Iranian Chamber of Commerce, said prior to the 2015 nuclear deal, “Some two-thirds of Iranian industry relies on German engineering products.”

Nasrin Amirsedghi, a leading Iranian dissident opposed to German trade with Iran who has written and lectured on the repression of women in the Islamic Republic, told that that “it is disappointing that such demands like from today’s current US ambassador today are forcefully announced” instead of 20 years ago, when the demands could have ousted the mullahs. “I am ashamed for Germany that despite its past it continues to support politically and economically such a regime in Tehran.”

The “Iranian regime’s goal is the destruction of Israel,” she said.

A Wednesday article in the BILD newspaper, Germany’s largest daily, said, “Iran has exactly two export hits: oil and terrorism.”

Grenell told BILD, “Every country is sovereign and can decide for itself on sanctions. But Germany, France and Britain, the ‘EU-3,’ say themselves that Iran poses a threat. Do they want to do business with a threat?” He added that “If so then all companies chiefs who want this should stand up and say: ‘we want to do business with the mullahs.’”

Benjamin Weinthal reports on human rights in the Middle East and is a fellow at the Foundation for Defense of Democracies. Follow him on Twitter @BenWeinthal