The head of the International Atomic Energy Agency, Mohammed ElBaradei, reached an agreement Sunday in Tehran but the United States said the issue falls short of addressing its concerns about uranium enrichment, Radio Free Europe said Monday.

The agreement allows IAEA oversight on Iranian studies concerning the conversion of uranium dioxide into uranium tetrafluoride, which can be refined to weapons-grade uranium, and an examination over suspicious radioactive contamination discovered at an Iranian technical university.

Gordon Johndroe, a spokesman for the White House, said the confidence-building measures were useful but emphasized the Bush administration's policy of making uranium enrichment too costly for the Iranians.