Iranian media reports say Foreign Minister Javad Zarif, during a telephone conversation with U.S. Secretary of State John Kerry, expressed Iran's "discontent" over the expansion of a blacklist of companies following a landmark nuclear agreement.
A State Department official confirmed the telephone call, saying the conversation "was focused on the way forward."
He said the two spoke on the phone during Kerry's overnight flight to Vietnam on December 13.
Iran has previously accused Washington of going against the November interim agreement by adding a dozen overseas companies and individuals to its blacklist for evading sanctions imposed on Tehran over its controversial nuclear program.
The U.S. decision led to a suspension of talks between Iran and the six world powers on implementing the deal.
But on December 15, Tehran said the talks would continue despite the move.
With reporting by AFP