An Iranian nuclear scientist who vanished in May 2009 defected to the CIA and has been resettled in the United States, ABC News reported on Tuesday.According to the report, which cites individuals briefed on the operation by intelligence officials, the defection of Shahram Amiri was deemed "an intelligence coup" in efforts against Iran's nuclear program.Relatives quoted in Iranian media have said Amiri researched medical uses of nuclear technology at a Teheran university.His disappearance, which Iranian authorities say came during a pilgrimage to Saudi Arabia, preceded the revelation of a second uranium enrichment facility that Iran has been building near the city of Qom, raising speculation that Amiri may have given the West information on it or other parts of the nuclear program. "The significance of the coup will depend on how much the scientistknew in the compartmentalized Iranian nuclear program," the reportquoted former White House counter-terrorism official Richard Clarke, anABC News consultant, as saying. "Just taking one scientist out of theprogram will not really disrupt it." Iranian Foreign MinisterManouchehr Mottaki said in October that "we have evidence of a US rolein disappearance of the Iranian national... in Saudi Arabia... There isevidence to suggest the United States was involved." ABCfurther reported that according to those people briefed on the case, Amirihad been extensively debriefed since his defection by the CIA, and thathe is said to have helped confirm US intelligence assessments about theIranian nuclear program.