Iran has said evidence and documents offered by the US to the UN nuclear watchdog against Tehran's nuclear program are not authentic.

"All evidence given by the United States against Iran's nuclear program is fabricated," Iran's envoy to the International Atomic Energy Agency (IAEA) Ali-Asghar Soltaniyeh told reporters in Vienna after the agency briefed its 35 members on Thursday.

The envoy's comments followed accusations by the United States and its allies that Iran was developing a military version of its nuclear program.

The Iranian ambassador called on the UN nuclear agency to preserve its impartiality and not to turn a blind eye on Iran's good cooperation.

"It is high time that the member states should have a complete picture in order to have a better judgment because… the board of governors has put pressure on the secretariat to give impartial, incomplete reports and has created for the past five years many misunderstandings," said Soltaniyeh.