The delegation of the International Atomic Energy Agency (IAEA), led by Olli Heinonen, IAEA deputy director, will meet with Iran's deputy nuclear negotiator Javad Vaeedi to discuss the Iran nuclear file.
Iran, which Western countries suspect of pursuing a secret nuclear weapons program, recently intensified cooperation with the IAEA, and invited weapons inspectors to visit a 40-MW heavy water reactor in Arak in late July.
Iran insists it needs nuclear power purely to generate electricity. President Mahmoud Ahmadinejad announced in early April the start of uranium enrichment on an industrial scale.
Iran has defied three consecutive UN resolutions against its nuclear program since last year. The six countries negotiating the dispute - permanent members of the UN Security Council plus Germany - have demanded that Tehran suspend all uranium enrichment before negotiating a solution to the dispute.