The United States maintained a hard line on Iran on Wednesday but admitted that it was not sure whether it could succeed in referring Iran's nuclear issue to the United Nations Security Council.

"We remain deeply concerned that Iran continues to defy the (IAEA) board's request," State Department spokesman Richard Boucher said at a press conference.

Boucher said the IAEA board was united in the view that Iran must cooperate fully with the IAEA and "must come clean about its program and suspend al enrichment-related and reprocessing activities."

Boucher said the United States had been insisting on referring Iran's nuclear issue to the United Nations Security Council.

"The process is underway. How far we will get to, whether we can get it or not, still do not know," Boucher said.

Boucher said the United States was still holding consultations with the European allies and "at this point I can not predict exactly where they will come out."

Iran has denied that it is seeking to make nuclear weapons and said its nuclear program is for peaceful purposes.

Source: Xinhua