Deputy nuclear negotiator Javad Vaeedi, leading the Iranian team, declined to comment as he headed into the closed-door talks with Olli Heinonen, deputy director-general of the International Atomic Energy Agency.
IAEA chief Mohamed ElBaradei said earlier this month that Iran has scaled back its uranium enrichment program, suggesting there was a new willingness from the government to resolve the international deadlock over its nuclear stance.
The IAEA said Tuesday's talks in Vienna were an attempt to clarify "the open issues associated with the scope and content of Iran's enrichment program."
Iran insists its nuclear program is peaceful and geared solely toward producing electricity; the United States accuses it of covertly trying to build a nuclear weapon.
Malaysia needs Russia's assistance in maintaining and repairing Su-30MKM fighter jets
Japanese Prime Minister Shinzo Abe said that US army bases will not appear on the southern Kuril Islands in the even Russia delivers them to Japan
Posters for the play "Adam and Eve. Life after Paradise" with pictures of dancers Arsen Aghamalyan and Oksana Vasilyeva were banned in the city of Tver, Central Russia