VIENNA: Western diplomats say Iran has started installing high-tech machines at its main uranium enrichment site that are capable of accelerating activity that can produce reactor fuel and - with further upgrading - the core of a nuclear warhead.

Iran already said last week that it had begun installation, but diplomats said at the time that the announcement was premature, with the enriching centrifuges on site but not yet being put into place

Three diplomats speaking to The Associated Press on Wednesday said, however, that installation was now well on its way, with 100 or more machines mounted. They demanded anonymity because they were not authorized to divulge confidential information.

Iran denies any interest in nuclear weapons and says it is enriching only for nuclear power, science and medical purposes.