"It is complicated, it is hard, it's going to take some time," said the official, who spoke on condition of anonymity.

The official said the administration of President George W. Bush thought that France, Britain and Germany, the so-called EU-3, have "a pretty good approach."

"We have to continue to be skeptical but have made it clear that we support the efforts, and the efforts are genuine, by the EU-3," the official said. "But we think that it is the best course and we think that it has not ran its course."

The foreign ministers of France, Britain and Germany, plus EU foreign policy chief Javier Solana, will meet Iranian negotiators in Brussels next Tuesday.

The EU-3 called a crisis meeting with Iran after Tehran announced it would resume uranium conversion work, a move that would violate a November accord on freezing nuclear fuel work and opening long-term talks.

Iran has agreed to hold off from resuming uranium conversion -- a precursor to the enrichment process -- pending the emergency talks in the Belgian capital.

The US administration official welcomed the fact that European powers had opposed attempts by Iran to resume uranium processing in a departure from their previous commitments.

The Russians have been very supportive by talking to Iran about the Bushehr reactor and ensuring that they would give back the fuel and that it would not jeopardize the proliferation regime the Europeans are talking about with the Iranians, the official said.

"There was some suggestion from the Iranian side about resuming some activities related to enrichment that would be inconsistent with the cessation arrangement," the official pointed out.

The official said the signal sent by the EU-3 was that the cessation arrangement needed to be respected and that the negociations needed to continue.

"We think that was a pretty good message and the Iranian side responded by suggesting some new conversations and hopefully will back off," the official added.

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