Foreign ministers and economic ministers of France, Germany and the UK announced that Washington should abjure sanctions against European companies working in Iran.
The letter from European ministers says that the European Union demands exemption from US sanctions for the European companies that already started concluding contracts with Iran after the Joint Comprehensive Plan of Action had come into force.
France's Minister for Economy and Finance Bruno Le Maire published the text of the letter on his Twitter account.
The letter, dated from June 4, is addressed to US Secretary of State Michael Pompeo and US Treasury Secretary Stephen Mnuchin.
"As allies, we expect that the United States will refrain from taking action to harm Europe's security interests," the ministers wrote.