Iran has said that three-day talks with the International Atomic Energy Agency, which ended Wednesday, were "constructive and positive."
The Iranian envoy at the United Nations nuclear watchdog IAEA, Ali-Asghar Soltanieh, who was present during discussions with IAEA's chief inspector Oli Heinonen and head of the Iranian Atomic Organization, Gholam-Reza Aqazadeh, said the meetings would continue.
Heinonen and his team were to leave Tehran for Vienna on Wednesday night, ISNA news agency reported.
The talks were technical in nature and did not deal with political issues, such as whether Iran would accept the latest offer by world powers to suspend uranium enrichment in return for political and economic incentives.
Tehran has said its nuclear programme is for peaceful purposes. But the United States and other Western nations want further guarantees that the Islamic state is not pursuing a secret weapons programme.