ANKARA, Turkey - The United States and other world powers might be ready to allow Iran to keep some of its uranium-enrichment program intact instead of demanding its complete dismantling, foreign government officials said yesterday.

Officials said some willingness to compromise might advance talks today in the Turkish capital between top Iranian envoy Ali Larijani and Javier Solana, the European Union's foreign-policy chief.

Recognizing that Iran would never accept a complete freeze, the powers are considering "a new definition of enrichment," one diplomat said. Under the proposal, Iran would could keep some of its program without actually producing enriched uranium.

State Department spokesman Sean McCormack denied that the United States was "considering any proposals that would allow the Iranians to retain any enrichment-related activities."

But another U.S. official who spoke on condition of anonymity suggested there was potentially more flexibility.

"We purposely left open the possibility that direct talks could happen by being a little less committed to the requirements to have a meeting," said the official. He alluded to previous demands of an all-encompassing freeze on all enrichment-related activities.

Iran is running more than 1,300 centrifuge machines at its underground facility at Natanz. Its ultimate 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.

The United States might accept a version of "cold standby" - allowing a set number of centrifuges to remain standing and assembled in series but not running, a diplomat said. Iran, he said, would likely push for keeping the machines operating, if not producing enriched uranium.

The six powers - United States, Russia, China, Britain, France and Germany - also want to reduce assembled and hooked-up centrifuges to fewer than 1,000.

A European official said hopes were that both sides could agree on at least "a different definition of suspension that we can work with."

With agreement to strive for a new definition of enrichment, Larijani and Solana may be able to sidestep a deadlock that for months has thwarted the resumption of negotiations over Iran's nuclear program, said the officials, who were familiar with the discussions with Iran or specialized in non-proliferation issues.