The International Atomic Energy Agency says Iran has handed over a great deal of information on its past nuclear activities, but it is too early to judge whether the program is for peaceful purposes only.
Responding to an IAEA resolution, Iran submitted by the October 31 deadline some 200 pages of what it says is a complete and accurate file about its nuclear program.
The IAEA says the documents are very detailed, and Iran has cooperated well in the last weeks.
But the U.N. nuclear watchdog agency spokesman, Mark Gwozdecky, says information provided by Iran earlier this year was often inconsistent.
"By June, that information had changed, as we extracted more new information, and confronted them with things they could not refute," he said. "By September, we had again confronted them with a whole new set of evidence and information that forced them to change their story in many ways again."
The IAEA says it is now examining the new information to determine whether Iran is secretly building nuclear weapons. Conclusions from the examination of the file will be submitted to the IAEA governing board by mid-November.
The United States has accused Tehran of maintaining a clandestine nuclear weapons program, which the Iranian government denies. But western diplomats have long questioned why an energy-rich country like Iran needs an ambitious nuclear program for civilian use.
The U.N. nuclear agency say it expects to receive a letter from Tehran some time next week, accepting the terms of an additional protocol to the Nuclear Non-Proliferation Treaty. Under that protocol, Iran would have to open its nuclear facilities to unannounced inspections. The IAEA board of governors meets at the end of November and, if doubts remain, could refer Iran's nuclear program to the U.N. Security Council for possible sanctions.