Britain, France and Germany said they would not back US efforts to unilaterally trigger the reimposition of United Nations sanctions on Iran, but said they wanted talks with Tehran over its ongoing violations of a 2015 nuclear accord.
Under Iran's 2015 deal with world powers to accept limits to its nuclear programme in return for the lifting of sanctions, a UN weapons embargo is due to expire in October. The United States, which exited the deal in 2018, says it wants to extend the embargo.
If the UN Security Council does not extend the embargo, Washington has threatened to trigger a so-called snapback of all UN sanctions on Iran, using a process outlined in the nuclear deal.
Such a move would be likely to kill the nuclear accord.
"We firmly believe that any unilateral attempt to trigger UN sanctions snapback would have serious adverse consequences in the UN Security Council," the foreign ministers of the three European countries (E3) said in a statement.
"We would not support such a decision, which would be incompatible with our current efforts to preserve the JCPoA (Iran nuclear deal)," they said after discussing Iran in Berlin.
European diplomats are working on a compromise, but it is unclear whether they will able to satisfy the United States as well as Russia and China, which like the E3 remain in the deal.