"We could not finalize the structured approach to resolve the outstanding issues regarding possible military dimensions of Iran's nuclear program," IAEA team leader Herman Nackaerts said.
He said another meeting will take place Feb. 12.
Voice of America said the IAEA hoped to get access to the Parchin military site, which Western officials suspect houses nuclear weapon projects.
Iranian government officials have maintained the site is only for conventional weapons and that a religious ban on nuclear weapons is binding on the government.
Notable deaths of 2014 [PHOTOS]