Iran's nuclear project has developed its own version of an advanced centrifuge to churn out enriched uranium much faster than its previous machines, diplomats and experts said Thursday.
They said that few of the IR-2 centrifuges were operating and that testing appeared to be in an early phase, with the new machines rotating without processing any uranium gas.
More significant, the officials said, is that Iran appears to have used know-how and equipment bought on the nuclear black market in combination with domestic ingenuity to overcome daunting technical difficulties and create highly advanced centrifuges.
Iran's uranium enrichment work has raised concerns in Washington and other Western capitals because it can produce the radioactive material needed for nuclear bombs. Tehran says it is only pursuing lower-level enrichment to make fuel for atomic reactors that will generate electricity.
Up until recent weeks, Iran had publicly focused on working with P1 centrifuges - outmoded machines that it acquired on the black market in the 1980s. Workers set up more than 3,000 of the machines in the large underground hall near Natanz, a city about 300 miles south of Tehran.
But diplomats, who spoke on condition of anonymity, told the Associated Press that Iranian experts now are testing a small number of more advanced IR-2 machines. They described it as a hybrid of the P-2 centrifuge once peddled on the black market by A.Q. Khan, the scientist who oversaw Pakistan's development of nuclear weapons.