The US has agreed to the idea of taking part in talks involving Iran and world powers with a view to reviving a landmark nuclear deal. Earlier, Iran vowed to limit its nuclear programme in return for the lifting of economic sanctions under the 2015 deal.
But former President Donald Trump withdrew the US from the deal in 2018, leading Iran to roll back commitments.
Now the US has expressed intent to rejoin
the deal under President Joe Biden.
State department spokesman Ned Price said the US would accept an invitation from the European Union to meet Iran for talks.
Senior EU diplomat Enrique Mora tweeted he was "ready to invite" all parties to talks, saying this was a "critical moment" for the deal.
Iran has not formally responded to the proposal.