The International Atomic Energy Agency (IAEA) says Iran is blocking access to some of its nuclear sites and continues to boost its stocks of enriched uranium.
The new movements further violate the country’s 2015 nuclear deal with world powers and complicate the already hobbled deal.
“The director-general is increasingly concerned that even after some two years the safeguards issues outlined above in relation to the four locations in Iran not declared to the agency remain unresolved,” the IAEA said in one of two quarterly reports on Iran.
It said in a confidential report cited by Western news agencies on September 7 that Iranian officials had also failed to answer questions including on uranium traces found at three undeclared sites.
The agency has condemned what it considered Iran's lack of cooperation in implementing its nuclear program monitoring mission.
"Since February 2021, verification and monitoring activities have been seriously impeded in light of Iran's decision to stop implementing its nuclear commitments,” the agency said.