The agreement on the timetable for nuclear negotiations was reached between EU foreign policy chief Javier Solana and Secretary of Iran's Supreme National Security Council Saeed Jalili.
"The parties are holding consultations on the place of negotiations," the source said, adding that the talks would resume very soon.
Solana, handed Iran's Foreign Minister Manouchehr Mottaki a package of new incentives from the Iran six - China, France, Russia, the United States, Germany and Britain - on June 14. The proposals offer political, security and trade benefits to Iran in exchange for its decision to suspend its nuclear program.
Iran is currently under three sets of relatively mild UN Security Council sanctions for defying demands to halt uranium enrichment, which it says it needs purely for electricity generation despite Western accusations that the program is geared toward weapon production.
Iran maintains that it has never been involved in research into the development of nuclear weapons.
