Muhammad el-Baradei told reporters in Vienna today that the International Atomic Energy Agency (IAEA) had seen "a fairly slow development" in Iran's installation of centrifuge machines.
These can enrich uranium into fuel for nuclear energy reactors, or, when the fuel is refined to a higher degree, nuclear-weapons-grade material.
Despite Tehran's denials, western powers suspect Iran's nuclear program is secretly aimed at producing nuclear weapons.
(Reuters, AFP)