The International Atomic Energy Agency has adopted a resolution that calls on Iran to provide sufficient cooperation with its investigation into nuclear substances found at undeclared sites between 2019 and 2020.

Reuters News Agency reported that the resolution proposed by Britain, France and Germany was passed by the IAEA's Board of Governors on Wednesday.

The resolution, which was adopted by a majority vote, calls on Iran to urgently cooperate with the investigation by providing access to the relevant locations and allowing samples to be taken.

It also urges Iran to reverse its withdrawal of the designations of several IAEA inspectors.

Iran has reacted sharply to the move. A spokesperson for Iran's Atomic Energy Organization said, "Western countries are expected to take the path of interaction and cooperation, instead of misusing international organizations and exerting pressure."

The international community is increasingly concerned about the issue, as Tehran has been producing uranium enriched to up to 60 percent purity. That far exceeds the limit set in the nuclear agreement with major world powers.