Iran's nuclear negotiator Saeed Jalili has written to European Union's foreign policy chief Catherine Ashton asking that the two sides set a timetable and choose a venue for the talks.
The official IRNA news agency says Jalili's letter was delivered Wednesday in Brussels, reiterating his call for a "constructive approach." There was no immediate response from the EU.
Previous talks have not resolved international suspicions that Iran's nuclear program masks a pursuit of atomic weapons. Tehran insists it's for peaceful purposes.
Iran first offered the new talks in February in response to a letter from Ashton.