According to the International Atomic Energy Agency (IAEA), Iran's nuclear program could serve both peaceful and military purposes.
Tehran has done nothing in recent months to clarify open questions about possible secret activities in the past, IAEA chief Rafael Grossi wrote in a report on Wednesday.
The IAEA "is therefore unable to confirm that the Iranian nuclear program is exclusively for peaceful purposes," Grossi wrote in the non-public quarterly report on Iran that was available to the German Press Agency.
Grossi also reported that Iran had been enriching more and more uranium in recent months.
Among other things, the country now has more than 55 kilograms of uranium with a purity of up to 60 percent.
According to experts, around 50 kilograms of this material are enough for a nuclear weapon if it were enriched a little higher to 90 percent.
Iran has repeatedly emphasized that the uranium will only be used for energy generation and other peaceful purposes.
According to Grossi, the IAEA has not had any insight into the production of new centrifuges used to enrich uranium for three months.
In June, Tehran had IAEA surveillance cameras removed.
In response to the United States' withdrawal from the international pact limiting Iran's nuclear program, Tehran has been violating the agreements contained therein since 2019.
Washington and Tehran have been negotiating about restoring the pact and lifting US sanctions for the last year.
Recently, among other things, the Iranian demand for the IAEA to stop investigating the open questions has prevented an agreement.