Iran has handed over information on its prior nuclear work to the International Atomic Energy Agency (IAEA), as required by the recent nuclear deal.
Observers say that the documents are necessary in order to know how far Iran is from completing a nuclear weapon, should it break the treaty. However, the IAEA acknowledged that it does not yet know if the documents give a full picture of the Iranian nuclear program.
Iran has frequently claimed that it had no intention of building nuclear weapons, but most other countries and intelligence agencies believe that to be a lie.
US legislators in particular have expressed their concern that Iran will not be honest about its previous nuclear work. President Barack Obama has tried to downplay the issue, arguing that the sanctions on Iran will only be lifted once Iran gives over all the necessary information.
The IAEA now has a month to analyze the documents it received. It will then meet with Iranian representatives in September and October to go over any remaining questions in private.
Lawmakers from the United States have also criticized this step, as the IAEA refuses to fully disclose its agreement with Iran. A number of Senators and Representatives fear that the organization will be too lenient with the Islamic Republic, and that there will be no other outside review.