Iran and the six major powers agreed during talks in Moscow to hold expert meetings in Istanbul on July 3, MNA reported.
EU foreign policy chief, who represented the major powers in the talks, also told a press conference that she would remain in contact with Iran's chief nuclear negotiator, Saeed Jalili.
Ashton also said that Helga Schmid, the deputy secretary general for political affairs of the European External Action Service, and Jalili's deputy, Ali Baqeri, will maintain contact, the Mehr News Agency correspondent in Moscow reported.
Ashton said that during the talks in Moscow, the major powers wanted Iran to agree to stop enriching uranium to a purity level of 20 percent.
The agreement to hold expert talks in Istanbul was made after two days of intensive talks between negotiators from the 5+1 group (the five permanent members of the UN Security Council and Germany) and the Iranian delegation.
The negotiations were a continuation of talks that were held in Istanbul on April 14 and in Baghdad on May 23 and 24.
After the Baghdad talks, Schmid and Baqeri were tasked with drawing up an agenda for the Moscow talks, and experts from the two sides were supposed to hold meetings to make the necessary preparations.
However, the major powers reneged on the agreements made during the Baghdad talks and preliminary meetings were not held.
After the first day of the talks, Baqeri told reporters that Iran had elaborated on the proposals presented in Baghdad during the negotiations.
He also described the meetings as "serious" and "constructive", adding that the Iranian negotiators had expressed their views on the proposals presented by the six major powers.
The main point of Iran's package of proposals is that the negotiating countries must recognize Iran's right to enrichment under the NPT (nuclear Non-Proliferation Treaty).