Diplomats say countries monitoring Iran's nuclear program have picked up information that the country's only power-producing nuclear reactor was damaged by one or more recent earthquakes, AP reported.
Two diplomats say long cracks have appeared in at least one section of the structure.
They demanded anonymity Tuesday because they are not authorized to divulge confidential information.
Officials in Tehran assured the international community after the quakes struck in April and early May that the facility at Bushehr, south of Tehran, was undamaged.
The plant is not considered a proliferation threat, but some nations are concerned about how safe it is.
Iran has refused to join an international nuclear safety convention and technical problems have shut the plant for lengthy periods since it started up in September 2011 after years of construction delays.