The Bush administration was dismissive Tuesday of Iranian suggestions that it might suspend uranium enrichment for up to two months to set the stage for negotiations over its nuclear program and to head off U.N. sanctions.

"To the best of my knowledge there has been no Iranian proposal," State Department deputy spokesman Tom Casey said. "There's been no change in the Iranian position."

Casey said, 'They have not agreed to suspend uranium enrichment activities for any length of time that I am aware of."

The spokesman said the Bush administration was proceeding with discussions with other nations on pursuing sanctions against Iran in the U.N. Security Council.

Casey's comments came a day after Secretary of State Condoleezza Rice left the door open to pursuing a possible compromise with Iran, based on reports that Tehran had proposed a temporary enrichment suspension.

Rice had said Iran had not made a formal offer, and she added that she had not had a chance to learn all the details of the Iranian suggestion. But rather than rule it out, she said, "The question is, are they prepared to suspend verifiably so that negotiations can begin?"

Casey said it was unfortunate that Iran has not given any indication that it would be willing to suspend uranium enrichment activities to pave the way for negotiations.

Casey said Rice will take up the sanctions issue with other diplomats attending the special session of the U.N. General Assembly next week in New York.

Undersecretary of State Nicholas Burns held a telephone conference with officials of other governments Monday and Tuesday and will continue with the talks later in the week, Casey said.

Casey said suspension of uranium enrichment remained a condition for negotiations with Iran over a package of incentives offered by the United States and the European Union. This included a U.S. offer of technical assistance to Iran for civilian nuclear power development.

The outlook for the Bush administration succeeding in pushing sanctions through the Security Council is not clear.

Russia and China have expressed reservations about imposing sanctions on Iran and called for further diplomacy. Both have the power to veto any resolution and thereby kill it. Some European governments also have seemed dubious about punishing Iran at this stage.

The council threatened Iran with sanctions in July if it did not suspend uranium enrichment as well as work on plutonium for nuclear weapons by Aug. 31. Iran let the deadline pass. It insists it is not trying to make nuclear weapons.