EU foreign policy chief Catherine Ashton is set to visit Iran.
"Ms Ashton will arrive in Tehran on Saturday night," the official IRNA news agency quoted Iran's deputy foreign minister Abbas Araqchi as saying on Tuesday.
He added that during her visit she would meet with President Hassan Rouhani and Foreign Minister Mohammad Javad Zarif.
According to Iranian media, Ashton will meet officials on Sunday before travelling to Isfahan the next day.
The last visit of an EU foreign policy chief to Tehran took place in 2008.
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Ashton is the lead negotiator for the P5+1 group of world powers, which is seeking a comprehensive agreement on Iran's controversial nuclear programme, and which plans to hold technical talks with Iran in Vienna on Wednesday.
"In this round of expert-level talks, we will review the issues related to (uranium) enrichment as well as tackling the concerns about the Arak heavy water reactor," Araqchi said.
The Arak site is of concern to the West because Tehran could theoretically extract weapons-grade plutonium from its spent fuel if it also builds a reprocessing facility.
In February, Tehran and the P5+1 - the United States, Britain, France, China and Russia plus Germany - agreed on a timetable and framework for the negotiations for an accord that would allay Western concerns about Iran's nuclear programme in return for the lifting of crippling sanctions.
Negotiators hope to reach a final accord by July 20, when an interim agreement reached in November is due to expire.
