Iranian intelligence ministry does not specify nationality of those held; European Union's Enrique Mora arrives to discuss reviving 2015 deal under negotiation in Vienna

IAEA head Rafael Grossi says Tehran has refused to clarify evidence of illicit uranium enrichment, as EU's Mora heads back to Iran in bid to get nuke talks back on track

The yet-unfinalized visit by coordinator Enrique Mora is a move in the 'right direction,' according to Iranian foreign ministry

16 Democrats vote in favor of symbolic measure demanding more restrictions against Iran, keeping Revolutionary Guard Corps on terror list

Rafael Grossi says UN agency also working to clarify Tehran's response to findings of traces of enriched uranium at three sites across Iran

As Israeli, US national security advisers meet in Washington amid stalled Vienna negotiations, Tehran calls for return to talks and blames US

Installation of IAEA surveillance equipment, which will monitor production in facility at Natanz site, comes amid Western efforts to restore the nuclear deal with Tehran

Iranian supreme leader blames the US for halted negotiations, urges Tehran's representatives in Vienna to continue despite 'America's excessive demands'

Iranian foreign ministry spokesman says he doesn't know if a deal will be made

Iranian FM Amir-Abdollahian claims Washington has recently aimed to introduce fresh 'excessive' demands at Vienna negotiations on reviving 2015 pact