Vienna - The heads of the Iranian Atomic Organization and the International Atomic Energy Agency (IAEA) started their meeting in Vienna on Thursday, to discuss Iran's cooperation with the IAEA and it's recent talks with world powers in Geneva.

Gholam-Reza Aqazadeh, Iran's nuclear chief, was expected to discuss with IAEA Director General Mohamed ElBaradei to discuss bilateral cooperation and how to proceed following the Geneva talks last Saturday.

The IAEA is still seeking answers from Tehran about past research projects that could be related to a nuclear weapons effort.

Besides ElBaradei, the IAEA's chief inspector Ollie Heinonen is participating in the meeting with Aqazadeh, sources close to the agency said.

Last Saturday in Geneva, Iran nuclear negotiator Saeid Jalili had met EU foreign policy chief Javier Solana and envoys of the five veto powers in the United Nations Security Council plus Germany.

At the meeting, Iran did not provide an answer to the world powers' demand that it suspend uranium enrichment in order to open the way for comprehensive talks on economic, political and nuclear energy cooperation.

Under a so-called "freeze for freeze" approach, the six powers - Britain, France, Germany, the United States, Russia and China - were offering not to press for additional Security Council sanctions against Iran if Tehran would agree not to expand its enrichment facility in Natanz. (dpa)