France's ambassador in Washington says world powers and Iran will probably miss an end-of-June deadline for a comprehensive nuclear agreement.
Gerard Araud says it's "very likely" there will be no deal in the next five weeks, or even afterward.
He says much technical work remains, meaning any understanding reached could just be "fuzzy air."
Araud spoke Tuesday at an Atlantic Council event alongside the British and German ambassadors to the U.S.
The three European countries are negotiating alongside the U.S., Russia and China.
The proposed deal would freeze Iran's nuclear program for a decade, while providing Iran tens of billions of dollars' worth of sanctions relief.
Iran says its program is solely for peaceful purposes. Many governments fear it harbors nuclear weapons ambitions.