Iran expended its nuclear enrichment capability by installing hundreds of advanced centrifuges in a uranium enrichment plant, the UN nuclear watch dog reported in a confidential document on Wednesday. The report said Iran continues to install the IR-2m centrifuges, which could promote its uranium enrichment significantly in Natanz enrichment plant. \"As of 15 May 2013, four cascades had been fully installed and one cascade had been partially installed with IR-2m centrifuges and empty centrifuge casings,\" the report noted. The IR-2m centrifuges, installed in the plant is presumed to be around 700 in number. The report also said Tehran has possessed 182 kg of 20-percent enriched uranium stockpile, 15 kg more than the agency\'s previous report, which, however, is still far behind the 240-250 kg needed for making a nuclear bomb.