"This report shows once again that Iran is refusing to cooperate with the international community," said White House spokesman Gordon Johndroe. "The Iranian regime's continued defiance only further isolates the Iranian people.
"We urge Iran to suspend its uranium enrichment and reprocessing activities or face further implementation of the existing United Nations Security Council sanctions and the possibility of new sanctions," he said.
The U.N.'s International Atomic Energy Agency has been looking into intelligence allegations of secret atom bomb research by Iran and the report pinned the blame for the standstill on Tehran's failure to cooperate.
Iran blamed the IAEA for the impasse.
The United States and some of its allies have accused Iran of enriching uranium to potentially build nuclear weapons. They have imposed sanctions, as well as offered a package of incentives in an attempt to encourage Tehran to stop its program.
Tehran has refused to stop enriching uranium, arguing it is for a civil energy program.
Iran seemed some distance from refining enough uranium to build a nuclear weapon, if it chose, the IAEA report indicated.
(Reporting by Jeremy Pelofsky and Mark Heinrich, editing by Bill Trott)
