The U.S. ambassador to Germany says the European mechanism designed to facilitate trade with Iran and avoid U.S. sanctions is "disrespectful" to Washington’s policies.

Ambassador Richard Grenell said in an interview published on February 10 in the German newspaper Frankfurter Allgemeine Sonntagszeitung that the financial mechanism, called Instex, is counterproductive to President Donald Trump's efforts to force Tehran back to the negotiating table over its nuclear program and other matters.

Grenell labeled U.S. policy as the "Trump Doctrine," explaining that "we use the strongest possible sanctions, while at the same time offering talks to see if that changes the behavior of certain states."

Germany, France, and Britain on January 31 launched a mechanism to allow financial flows to be sent to Iran that would not violate U.S. sanctions in an attempt to keep alive the landmark 2015 nuclear deal with Tehran.

The special-purpose financial vehicle will allow European firms with legitimate business interests to use barter techniques to conduct business in Iran.

The plan focuses on areas not targeted by U.S. sanctions and in the beginning centers “on the sectors most essential to the Iranian population – such as pharmaceutical, medical devices and agrifood goods,” foreign ministers from the three countries said.

Germany, France, and Britain -- which signed the nuclear deal along with the United States, Russia, and China -- have been working hard to keep the accord alive after Trump announced in May he would withdraw from the deal and reimpose sanctions on Tehran.

Based on reporting by Frankfurter Allgemeine Sonntagszeitung, dpa, and Tiroler Tageszeitung.