Observing that Iran has made a "serious miscalculation" by paving the way for resumption of uranium enrichment, the United States has said that there was not much of an option than referring Tehran to the United Nations Security Council if negotiations have run their course.

"I think that the Iranian regime has made another serious miscalculation by their latest actions, and we are engaged in some intensive diplomacy right now. We are talking with our European friends and others about how to move ahead and those discussions continue," White House Spokesman Scott McClellan said.

• The Iran vote and after

We believe that if the negotiations have run their course and Iran is not going to negotiate in good faith, then there's no  other option but to refer the matter to the Security Council. If that happens then we would talk about what actions need to be taken at that time," McClellan said.

The Bush administration has been saying of late that it had the votes to haul Iran before the Security Council, but that it was giving diplomacy more time.

However, the clear impressions are that Washington has quite some way to go in fine-tuning the approach with Russia [Images] and China.

Moscow [Images] has been critical of Tehran, but does not appear to be too keen on any rushed course. Besides, Beijing [Images] is also not greatly enthusiastic about taking Iran to the Security Council.