The report, expected later today, is significant because it is linked to the lifting of sanctions on Tehran over its nuclear program.
Yukiya Amano, the head of the UN's International Atomic Energy Agency, has already said that his report won't be "black and white."
But he must present a final report that says Iran has met all deadlines in supplying information requested by the IAEA for the agency's 35-nation board to approve closure of the nearly decade-long investigation.