Iran and the six world powers that negotiated the 2015 landmark nuclear deal have released previously restricted documents in a bid to dispel suspicions that Tehran is cheating on the deal.
The documents were posted December 23 on the website of the UN nuclear watchdog, the International Atomic Energy Agency.
Some of the documents were dated back to January 6 of this year, just before the deal was implemented.
At the time the agreement was concluded, Iran had more than 100 kilograms of liquid or solid waste containing low-enriched uranium as part of its enrichment activities.
Some of the material remains and the newly released documents declare the low-enriched uranium it contains as "unrecoverable."
That means it can't be considered part of the 300-kilogram maximum stipulated in the deal.
Critics of the deal have watched closely for any sign that Tehran might be circumventing its restrictions.
Under the agreement, Western powers lifted crippling economic sanctions on Iran.