U.S. officials are closely following the situation in Iran. But they are refraining from specific comments about developments in the struggle between reform politicians and the conservative Guardian Council out of concern it might be seen as American interference.

At a news briefing, State Department spokesman Richard Boucher limited his remarks to a general expression of support for a free electoral process in Iran.

"We've always been supporters of free and fair elections," he said. "We've always been supporters of the idea that the Iranian people should have a right to decide their government and their government's policies. We urge the Iranian government to respect the Iranian people's wish for a genuine voice through free and fair elections."

Mr. Boucher also said the United States has made clear its concerns about the status of political freedom and human rights in Iran and is watching the events unfolding in Tehran in that context.