Talks with Iran aimed at ending a long standoff on explaining the origin of processed uranium particles found at apparently old but undeclared sites are at "a very difficult juncture", U.N. nuclear watchdog chief Rafael Grossi said on Wednesday.
Grossi, who is due to report on the issue to the International Atomic Energy Agency's Board of Governors before a quarterly meeting that starts on June 6, told a panel discussion at the World Economic Forum in Davos he hoped the time between now and when he produces that report is put to good use.
(Reporting by Francois Murphy; Editing by John Irish)
