BRUSSELS (AP) - The United States denied Tuesday that it is considering proposals that would allow Iran to partially retain its uranium enrichment program. "We're not considering any proposals that would allow the Iranians to retain any enrichment-related activities," State Department spokesman Sean McCormack said. "We would hope the Iranians would take us up on the offer for negotiations, but the conditions for entering those negotiations are the same."

Earlier, foreign government officials said that the United States, Russia, China and key European powers may for the first time be ready to allow Tehran to keep some of its uranium enrichment program instead of demanding it be completely shelved.

Speaking on the eve of talks between top Iranian envoy Ali Larijani and Javier Solana, the European Union's foreign policy chief, the officials - some of them diplomats, others based in their capitals - said the discussions were key because for the first time they could try to sidestep the deadlock over uranium enrichment by trying to agree on a new way of defining it.

McCormack said that Washington fully supports Solana's efforts.

Iran now is running more than 1,300 centrifuge machines and - as a prelude to enrichment - has recently coated their insides with minute amounts of the uranium gas that is used for enrichment itself, according to an internal document of the International Atomic Energy Agency, the UN nuclear agency.

Iran's ultimate stated goal is to run 50,000 centrifuges a year, enough to churn out material for a network of nuclear power generators - or a full-scale nuclear weapons program, should it choose to do so.

One of the diplomats said recognition by the United States and its allies that Iran would never accept their earlier demand of a full freeze dictated a decision to contemplate a new definition of enrichment that would allow Tehran to keep some of its program intact without actually turning out enriched material.

"The prize is the 50,000,” he said, alluding to attempts by the six world powers to prevent Iran from developing its full-scale program at its enrichment facility at Natanz. He, like other government specialists in nonproliferation and Iran's nuclear program who spoke to The Associated Press, demanded anonymity because their information was confidential.

The last face-to-face talks between Solana and Larijani were more than six months ago, and they foundered over the same issue. Solana, representing the United States, Russia, China, Britain, France and Germany, demanded that Iran shelve not only fledging enrichment efforts but all linked aspects, including assembling centrifuges to enrich and facilities to house such plants. Tehran refused.

The approach on both sides might make a compromise easier, because of a new willingness to examine possible ways of redefining an enrichment freeze, said the officials, who spoke to The Associated Press on condition of anonymity because their information was confidential.

Iran now is running more than 1,300 centrifuge machines and - as a prelude to enrichment - has coated their insides with minute amounts of the uranium gas that is used for enrichment itself, according to an internal International Atomic Energy Agency document.

Iran's ultimate goal is to run 50,000 centrifuges a year, enough to churn out material for a network of nuclear power generators.

One of the diplomats said recognition by the United States and its allies that Iran would never accept their earlier demand of a full freeze dictated a decision to contemplate a new definition of enrichment that would allow Tehran to keep some of its program intact without actually turning out enriched material.

"The prize is the 50,000," he said, alluding to attempts by the six world powers to prevent Iran from developing its full-scale program at its underground enrichment facility at Natanz.

He said the United States was favoring cold standby - where a set number of centrifuges are allowed to remain standing and assembled in series but not running.

The six powers also wanted to reduce assembled and hooked-up centrifuges to less than 1,000, so - should Larijani and Solana agree that there was further room for discussion - numbers also would likely play a role, he said.