The Trump administration pulled America out of the 2015 deal a year ago, saying it does nothing to stop Iran from developing missiles or destabilizing the Middle East. The Europeans insist that the pact is an important pillar of regional and global security and was never meant to address those other issues.
The E.U. powers say they "regret the re-imposition of sanctions" by the U.S. and remain "determined to continue pursuing efforts to enable the continuation of legitimate trade with Iran."
The Europeans have set up a complicated barter-type system to skirt direct financial transactions with Iran and so evade possible U.S. sanctions. The workaround, dubbed INSTEX, is not yet operational as Iran has not completed its part of the scheme.
The bloc said it plans to push ahead with "the operationalization of the special purpose vehicle 'INSTEX'."
The E.U. has also introduced a so-called "blocking statute" protecting European companies from the effects of U.S. sanctions, but many international corporations do more business in the United States than in Iran and have already severed ties there rather than risk running afoul of Washington.
In a message implicitly directed at the U.S. administration, the E.U. powers said "we call on countries not party to the (deal) to refrain from taking any actions that impede the remaining parties' ability to fully perform their commitments."
Despite the heated rhetoric, the Europeans insist that only the International Atomic Energy Agency can judge whether Iran remains in compliance with the nuclear agreement. More than a dozen reports have shown that Tehran is respecting it so far. A new report is due at the end of May.