The European Union says its senior diplomat will meet Iran's top nuclear negotiator on May 15 as a follow-up to the last round of six-power negotiations on Tehran's nuclear program.

That meeting in Almaty, Kazakhstan, ended on April 6 with the two sides still far apart. The six want Iran to stop enriching uranium to a level just a technical step short of the grade used to arm nuclear warheads. Iran says it has a right to enrich for energy, medical and research purposes and insists it does not want atomic arms.

An EU email from Brussels announcing the May 15 meeting in Istanbul offered no details. But the EU's Catherine Ashton and Iran's Saeed Jalili will likely discuss whether there is enough common ground to schedule new negotiations.