Iran has added more uranium enrichment centrifuges at its underground Fordow nuclear plant, diplomats report.

The facility is buried deep underground in order to minimize the risk of an attack on its operations.

A Western diplomat registered with the United Nations’ International Atomic Energy Agency (IAEA) said this week it is believed Iran continues to install centrifuges at the plant.

“Iran continues to build up enrichment capacity,” the official warned. “We think that they have continued installing centrifuges at Fordow. We think that their pace has continued the same as it was, which was pretty rapid.”

The next IAEA report on Iran’s activities, expected in mid-November, may state the Islamic Republic is near completion of centrifuges at the plant, another envoy said. Yukiya Amano, head of the Vienna-based IAEA, said in London his staff continues to monitor Iran’s attempts to hide evidence of experiments performed at one of its military bases.

Israel has consistently warned that Iran’s uranium enrichment program is not solely intended for peaceful domestic activities. The Islamic Republic has defied every international attempt and all sanctions by the U.N. Security Council and other international community members aimed at persuading Tehran to halt its nuclear development activities. Its leaders have also repeatedly vowed to annihilate the State of Israel, most recently in speeches delivered this past August in advance of the nation’s annual “Qods (Jerusalem) Day.”