Talks between the U.N. atomic watchdog and Iran aimed at prising answers from Tehran on unexplained uranium traces have been delayed, narrowing a window to make progress or risk undoing a wider push for detente with the West, three diplomats said.
"It's been pushed back several weeks regarding the April start. Could be as little as two," a European diplomatic source said, adding that the reason was technical.
Two diplomats also said there was a delay, one of whom said the IAEA delegation would be headed by inspections chief Massimo Aparo.
When asked about the delay, an IAEA spokesman said only: "A date in April has been confirmed." Iranian officials did not immediately respond to requests for comment.
The IAEA has said it is "deeply concerned" at the prospect of undeclared nuclear material in Iran. It says Iran has not credibly explained the first particles it found, at a site in Tehran that Iran said was a carpet-cleaning facility, and is seeking answers on those found last year at two other sites.