WASHINGTON: The United States on Thursday maintained its demand that Iran suspend its uranium enrichment as a condition for Washington participating in formal nuclear talks with Tehran, although it did not rule out less strict pre-negotiations.

"We have talked to the Iranians previously via the P5-plus-1 and Mr. Solana about various ways to get to full-blown negotiations," State Department spokesman Sean McCormack said, referring to grouping of Britain, China, France, Germany, Russia and the United States, as well as EU foreign policy chief Javier Solana who has engaged Tehran on nuclear issues.

"In order to get to those full-blown negotiations where you have the US and the other five members of the P5-plus-1 present at the table with the Iranians, they are going to have to suspend their enrichment-related activity.

"And of course there would be a suspension of activities in the (UN) Security Council during that," McCormack added.