Iran says that, despite U.S. condemnation, it has begun uranium enrichment at its underground nuclear facilities in Ferdo, adding that all of its activities are under the surveillance of the International Atomic Energy Agency.

The Associated Press reports that Iran insists the enrichment process is used solely for medical and peaceful purposes.

Ali Asghar Soltanieh, Iran’s representative to the IAEA, told Press TV that the Fordo facility, which is built inside a mountain near the holy city of Qom, has been under the IAEA’s strict surveillance during every step of its development.

IAEA spokesman Gill Tudor said in an email that “all nuclear material in the facility remains under the agency’s containment and surveillance.”

The U.S. and Britain, however, have expressed concern over Iran’s decision to go ahead with its enrichment plans.

The West has been troubled by possible military dimensions to Iran’s nuclear program. Iran insists, however, that it has no nuclear military ambitions.