ISTANBUL -- EU foreign policy chief Catherine Asthon has held "very long and useful discussions" with Iranian Foreign Minister Mohammad Zarif in Istanbul on advancing talks over Tehran's disputed nuclear program.
Spokesman Michael Mann said Ashton and Zarif "explored different possibilities as part of an ongoing process" during their unannounced May 26-27 talks.
He added that Ashton and Zarif recommended that an expert-level meeting should take place soon.
The EU says the next round of six-power nuclear talks with Iran has been scheduled for June 16-20 in Vienna.
The previous round of negotiations in Vienna earlier this month ended in disappointment with the parties far apart in drafting a text of a comprehensive agreement that would further ease Western sanctions on the country in exchange for Iran lowering its enrichment of uranium.