VIENNA, March 1: Iran rejected a request by UN nuclear inspectors to return to its Parchin military base, where Washington suspects Iran might have conducted tests linked to nuclear bomb-making, the U.N. atomic watchdog said on Tuesday.

Several months after their initial requests, Iran Permitted U.N. inspectors to visit Parchin in January. During this visit, inspectors told Iranian officials they would like to visit an area not covered in that inspection, the agency said.

Deputy chief of the International Atomic Energy Agency (IAEA), Pierre Goldschmidt, quoted Iran's response in a speech to the agency's board as saying: "The expectation of the IAEA in visiting specified ... points in Parchin Complex are fulfilled and thus there is no justification for an additional visit."

Iran is not required to allow the IAEA into sites like Parchin, where this is no clear sign of nuclear activities. But, Western diplomats on the IAEA board said, permitting agency inspections at such sites was crucial to building confidence that Tehran's nuclear plans are peaceful.

Iran says its nuclear intentions are limited to the generation of electricity, but Washington accuses it of using its nuclear programme as a cover to build an atomic bomb.

Mr Goldschmidt also said a December visit to a uranium conversion plant at Isfahan had "revealed extensive underground excavation activities which Iran had failed to report in a timely manner to the agency as required".

This excavation was the digging of a tunnel under the Isfahan plant, which Iran has said could be used to store equipment to protect it in case of U.S. or Israeli attack. -Reuters